As far as the Arc having an outsized impact on the game, I agree with that, but I don't agree it's for the worse. It provides a means for newer players to at least get some of the benefits that long-term players have (and I'm saying that as a long-term player), and frankly I think 1.9 leveling groups are good for the social aspect of the game since it can be a tool for establishing new alliances. In addition, other GBs such as Traz and CF also have very large impacts on gameplay. Admittedly not to the level the Arc does, but if we start clearing out the Arc (metaphorically speaking; I know you're not actually calling for Arcs to be deleted-yet) because it fundamentally alters the paradigm of the game I think you have to throw out Traz and CF with it
While I'm not entirely in disagreement, I'd point out that the paradigm-altering aspects of Traz and CF are drastically amplified by the existence of the Arc. A level 10 Chateau and Traz while certainly very strong and useful buildings are not game-breaking by any means. Taking them to say level 70 would be extraordinarily expensive (by the time you're at level 50 it'd be a net cost of about 1200 FP per level) if it weren't for the Arc. Bear in mind you have to also view that 1200 FP through the lens of not having level 60 FP producing GBs already as well. While you certainly could make the decision to get a positively broken Chateau without an Arc it'd come at the cost of not working on other GBs for a very long time.
In a world with level 80 Arcs already:
Getting your own level 80 Arc (from 10): ~21k FP
Adding a level 70 Chateau and Traz (from 10): ~21k FP each
In a world without arc ever existing:
Getting a level 70 Chateau (from 10): ~66k FP
So... by the time you would've got a level 70 Chateau, you've got a level 80 arc, a level 70 chateau, and could have thrown in a free level 70 Traz as well. Nevermind that a good portion of the FP in the arc case is also funded by sniping hoodies, 85% donations to willing friends, etc. Or that you actually have to work for the blueprints in the non-arc-proliferation case.