As a rule of thumb, the longer a media franchise remains active, the more likely it is to gravitate away from its original charm points. Granted, change or experiments are never necessarily a bad thing, but in the case of Milky Homes, they've overstayed their welcome shortly after they arrived.
Anyone acquainted with Tantei Opera Milky Holmes- or, hell, anyone who so much as saw images of it- knows that it's not particularly melodramatic or deep. It's quirky, zany, wild, and arguably shallow; but I, for one, wouldn't have it any other way. The first season's comedic direction successfully produced hilarious results, later to be improved to downright masterful levels in the the second season, Dai 2 Maku. By all means, it was the franchise's prime, but almost inevitably, such levels of quality were not here to stay. There wasn't much to worry about the the time; Milky Homles - Alternative were two short specials that, while not executed very well, were still welcome additions to the franchise, presenting a "what if" scenario that would've presumably later lead to a third season that's back to what Milky Holmes is really about.
"The Age of Detectives. The two flowers, vying for beauty. Their names are the Detective and the Phantom Thief"... if nothing else, this basic setting was retained in Futari wa Milky Holmes, the third season in the franchise, and a canon semi-direct continuation to the second season. As far as the story's concerned, it doesn't exactly connect with the final events of the previous season, but continuity was never really Milky Holmes' strong forte; or rather, it was never all that crucial to proper enjoyment of the show.
Futari, as its name suggests, stars two spunky aspiring Detective lolis. The story revolves around them solving crime (which is apparently detective slang for "physical violence" in this show) under a secret identity, incurring the wrath of the local Phantom Thief group, as well as a certain drill-haired police detective. In a way, the existence of new protagonists was the show's initial warning signal, signifying that this might not have been the classic Milky Holmes coveted by its fans. "Where are the Milky Homles?" "Where is G4?" "Who are Arsene's breasts?". Such questions may arise. As previously mentioned, though, change is never necessarily a bad thing. Some modifications of the cast are not nearly enough to bring a show to ruins, much less a franchise... and thankfully, every relevant character from the previous seasons appears in one way or another, but that's a story for another paragraph. For now, let's focus on our protagonists.
Kazumi and Alice, together known as "The Feathers", nab the spotlight.
Kazumi has a four-leaf clover hairpin, and Alice wears a nifty hat. In fact, when in their Detective outfits, they BOTH wear pretty nifty hats.
The above description was the absolute most I could do to make them sound interesting.
In a comedy setting, they would be bland. In a "serious" setting (which is what Futari is- or rather, strives to be), they would still be bland. Their personalities are mundane. Their attempted character development is miniscule and in the long run meaningless. Their Toys allow for relatively little variety in the combat scenes. They were presumably written to be "serious" replacements to the Milky Holmes, much like Alternative's Milky Holmes were "serious" replacements to the previous seasons' Milky Holmes. As a side note, seasons 1-2 and even a certain episode of Futari (and the original PSP game, worth noting) proved that it's possible for the Milky Holmes to be competent, powerful leads while still retaining their quirkiness and charm, but it's rarely taken to its full advantage. Instead, we get either Alternative's butchered Milky Holmes who are essentially glorified henchmen for Opera Kobayashi, or The Feathers, who can easily be mistaken for minor one-off characters at best, and cardboard cutouts at worst. That's not to say Futari is without its merits, but a decent chunk of its flaws can be pinned on The Feathers. That said, I gotta give credit where credit is due: the chemistry between the two is for the most part not half bad, as are the conflicts they have between themselves.
The resident rogues gallery, Color the Phantom (or "Colored Phantoms", which makes a lot more sense as a name, but that's precisely why I'll stick to the former), is thankfully less banal. Once again, they're not as memorable as the Phantom Thieves Empire, but at this point, that's to be expected. Their designs, however, actually invoke a gentleman thief aura, and their members are diverse and not as predictable as they may initially seem. It would not be an exaggeration to say that they carry the entire plot on their shoulders, for better or for worse. They interact splendidly with The Feathers, and while they're not the best villains in the franchise by a landslide, they're the ones most suited to be The Feathers' rivals... take that as you will. Furthermore, much against all expectations, the story improves tremendously with the introduction of a third party, Visconte. The boundaries between good and evil are blurred, resulting in a more interesting Detective vs. Phantom Thief conflict than the series initially seemed to offer. As far as the lead cast is concerned, the series' strength is with its antagonists. Yet whenever returning characters from previous seasons appear, they serve as a quick snap to the reality that you're watching a show where borderline extras are more interesting characters than the primary protagonists and antagonists, or so they should be, if the previous seasons are an indication.
Apparently, they aren't. To briefly talk about them, the Milky Holmes take on a mentor role in Futari, and each scene with them is marvelously ripe with attempts to make them appear to be the same clumsy bunch that were previously in the spotlight. Their defining character traits are virtually removed, to the point where they can easily be fused into one character under the archetype of "clumsy Detective mentor girl" and no one would be any the wiser, nor would their presence in the story be different at all. Kokoro, the grumpy and cocky policewoman, is now reduced to merely "the grumpy policewoman". Her mischievously arrogant nature is mostly gone, and in its place, her shtick becomes being moody at anything and everything for little reason. The rest of the G4 are all but absent, save for a handful of scenes. The Phantom Thief Empire's appearances are rather unnecessary- it at times appears as if they were shoved in at the last moment to solidify Futari's connection with the rest of the seasons. None of the recurring characters have any notable bearing on the plot, but with the Phantom Thief Empire, merely their presence as minor characters feels depressingly pointless.
The animation quality and art direction is mostly you'd expect. Nothing jaw-dropping, but definitely solid. Futari actually improves upon its predecessors in that regard, although not by much; the animation rarely falls behind, and the character's facial features (and to a lesser extent their outfits) are overall done better than ever. The voice acting also manages to be solid despite being somewhat amateurish, and the soundtrack is improved overall, with the exception of the barely subpar opening and ending songs. Basically, the production quality is mostly either identical or improved (the episodes themselves are about 10 minutes long, which would normally imply rushed pacing, but this is surprisingly not the case- there are no pacing problems despite the running time constraints), so as expected, what brings it down is the attempt to make Milky Holmes' basic setting work in an excessively serious story. Is it a bad show, though? I wouldn't go that far. As a standalone show unrelated to previous Milky Holmes entries (which nullifies the disappointment factor), it is, in one word, average. Not great, but during its airing time, made for a cute 10-minute distraction.
It should be noted, though, that perhaps the most baffling part about this series' attempt at melodrama and action is how the previous seasons themselves already had some semi-dramatic story branches, and even many impressively well done action scenes. The two aspects which Futari tries its best to succeed in, but to little avail. This is because unlike its predecessors, Futari disregarded any whimsical and over-the-top themes and took itself too seriously for its own good, when Alternative had already proved that it simply wasn't meant to be. The setting of Yokohama definitely allows for stories that are more than just whacky lolis like the Milky Holmes doing funny things, but for it to work successfully, it needs to be approached with the proper mindset; one that's aware of how the Milky Holmes universe is insane enough to gave birth to a character capable of using his erect nipples as swords, and takes advantage of that insanity.