TL;DR at the bottom
Okay, so it's none of the 'professional and long' reviews you see often. Just felt like it would be great to give you a short glimpse on this anime, since I'm that kind of person who needs to be reassured that an anime is worth watching, and that's usually by checking out trailers or reviews (mostly to see if there are any positive reviews, because I mostly watch non-popular anime). Either way, is it worth watching? Yeah, definitely. There are only 4 episodes at the moment and I will update the review once it finishes airing, but for now, jump in as soon as you can, so you keep up with the flow and don't need to do an all-nighter as I do all the time when watching anime (updates later below).
Now, I don't talk about people, yes you, who despise or dislike harem / ecchi genres. I, in particular, see no problem in watching these genres as long as it's not over the top or has actual plot. Maybe this show is a bit similar to a cliche, what is a strong MC; hides the powers; has a dark past; blah blah... But the execution itself and the kinda original spin of the cliche is what I like, because it reminds me of Konosuba, No Game No Life, Mondaiji-tachi, Gakushen Toshi Asterisk (even though it didn't have insane ratings) and such shows (ex. No Game No Life has an interesting plot to me, and it's good, further more it includes comedy, the MC doesn't strain / limit himself nor his character acting however he wishes, yet knows his abilities and thinks about them and proceeds knowing he can do this or that). That is basically why, you should watch this show, since it reminds of those shows, yet it's original. The MC is similar to a one of NGNL / Mondaiji-tachi, yet it is original in ways, because he's not too OP, however has a lot of knowledge. The plot is growing around the place where he works, yet the story has a great flow, considering there's a lot of stuff happening and yet it all makes sense. It keeps me pumped waiting for the next episode, so I do recommend it to you.
Plus, kawaii girls, what else do you need?
You get shironeko (white cat), Rumia, the calmia and kawaiiaa (and nobleaaa, too, apparently), and a bunch of students who adore the teacher who didn't even want to work for the school in the first place (and was forced by the carelessly careful Celica. Seriously, they're close, I can tell that), but probably knows more than most of the teachers there considering the popularity he's gained.
Keep in mind I have no idea what the show is like in LN, nor I have read it, because I love watching the animations rather than reading (probably due to my photogenic memory that prefers remembering animations, and not the pages), so I take no responsibility if it's worse, or whatsoever, in the LNs (I believe I've seen someone tell it's worse or better).
• Story - 8/10 (the flow is fine, fillers are fine, fan-service is fine, everything is preserved, nothing distracts you from the action and flow, maybe just not enough epic fights that give you those chills that I love)
• Art - 9/10 (it's fine, quality is truly amazing, although I disliked one moment in the episode about the quality at one part because of how the quality was sacrificed during fast-pace action in order to keep the animation smooth without letting the people to notice, however it's not possible to see it so easily so it's fine.)
• Sound - 10/10 (can't judge it, fine by me, I can hear even the birds, so it's goody goody for me, even objects falling have great sounds)
• Characters - 9/10 (don't expect much from a harem, this is a lot already because to me they seem unique in the sense of communication and their placement and such, but considering the main character, he has changed quite a lot compared to the start of the show)
• Enjoyment - 10/10 (seriously, it's fun, it kept me watching, I liked it, and I wait for the next eps. same as for when Konosuba 1/2 aired)
• Overall - 9/10
It's been a long time since I updated this review. I want you to know that it's really worth watching. I myself love when there's romance in anime, however I prefer it preserved. In this particular one, well it's a typical harem, except that the teacher doesn't actually let it to be a harem, he actually represents a teacher as the anime gets going, even though careless he would seem, he's a mastermind.
No idea how about you, but I loved the ending. I had various ships throughout the anime, and I couldn't really decide. I myself like romance, but I really don't even mind if it's not there as long as the author doesn't tease me to nerves. I loved it, I personally was amazingly satisfied by the ending and what was the last conversation of the whole pinnacle. I wished to see more and to see the romance develop, but on the other hand I guess it would push out the action and mystery out of it then, unless it's kept to minimal.
I recommend you to watch it, no matter if the start or some parts feel like bore or unacceptable to you, I have no problem with harems and ecchi genres, and I fully advise you to watch this. It is completely not over the top and I ensure you will have both great time, and be satisfied. It has action, comedy and mystery in it, at least for me. I'm pretty sure it's a good one this year.
What are you doing?
Start watching, you bakaaaa!