Gundam: Reconguista in G (from hence forth RG) is an ambitious project from a man who made the Gundam metafranchise what it is today. The show takes some big risks, but unfortunately, the execution leaves much to be desired.
First some back story. When Tomino produced the original Mobile Suit Gundam, he was struggling with deep depression and extreme suicidal thoughts. This led to his signature "Kill'em All Tomino" storytelling that bears a remarkable resemblance to George R.R. Martin's way of storytelling today--develop characters, get the audience invested, then give them the axe. By the mid-90s, however, Tomino was receiving treatment and began to reverse his dark disposition. He was less inclined to "Kill'em All" and more inclined to work out happier endings for his characters. This can be seen quite clearly in Turn A Gundam. In short, the Tomino who produced RG might as well be a different person entirely from the Tomino who made MSG in the 1970s. He is happier, more at peace mentally and spiritually, and less inclined to the brutality he once showed his characters as avatars of his own psychological struggles. However, many of his inspirations--Star Wars, Star Trek, and others--have remained the same and are quite clear in RG.
Now, the best way to describe RG would seem to be a conceptual sandbox of all the ideas Tomino came up with in the 35 years since the original Mobile Suit Gundam. We have already seen him do this once in Turn A Gundam, and now again in RG. A lot of the ideas are actually quite good, and if you use your imagination a bit, you can even see where he is going.
Also, we need to get something out of the way--RG has a lot of the usual Gundam tropes that have in many ways shaped anime as we know it today. You've got your talented pre-teen. Your Char Aznable masked enemy. Your invasion force from space. And, as often happens in Tomino, a "real" enemy revealed (twice) in the storyline that changes the way things are headed. If you are a Gundam fan of any magnitude, these can be forgiven, and perhaps even enjoyed. But they might be groan-worthy for newcomers to the franchise.
Now the problem is that all of this is done sort of haphazardly. It never really feels like the characters develop much or that there is ever a credible threat in the show. Yes, there are plot twists and big reveals, but there is not much foreshadowing done and the characters don't really go through arcs in reaction to them. Compare Bellri, the main character of RG, to Amuro, the main character of MSG. Amuro suffers clear PTSD in reaction to the events of the series, and we, the audience, experience these traumas with him. Bellri on the other hand pretty much starts and ends exactly the same way. Though he experiences much and learns even more, he never really develops beyond the person we are first introduced to in Episode 1. This is a problem that exists in ALL the characters in the show. Motivations are assigned to them, but never really owned by them.
Likewise, it seems like Tomino had planned to connect the Reguild Century more to the Universal Century, but all that really happens is a few one-off lines about the UC and some cameos of UC tech and locations. The show's main premise is that the human race has been limited in its expansion and use of technology on the planet Earth due to a system of beliefs developed at the end of the UC called "SU-Cordism". But the show never really outlines what the specifics of that system are. Indeed, it seems like SU-Cordism is a philosophy directly descended from Char Aznable's desire to clear the Earth of humans to allow it to recover, but this is never firmly established. Likewise, the signature of Tomino--Newtypes--are hinted at a few times but never expressly addressed, leaving some major questions over the evolution of humanity that had been raised throughout the UC Gundam series.
All in all, for a diehard Gundam fan, the show is enjoyable, but far from perfect. Hopefully, the places and ideas it established may form the basis for other materials in the Reguild Century that better trace its linage to the Universal Century. Though, overall, if you are on the fence about watching this series, you can probably safely give it a pass for now. For a similar series that has ideas on par with RG, I recommend checking out Gundam AGE.