It's pretty silly that the people complaining about how overpowered concentrate dev is are actually complaining about the weaker part of it, i.e. the economic effects of moving dev around. They see 3000 dev capitals and think it simply must be overpowered, while in reality the economic consequences are questionable. In terms of long-term resources, 20% of the dev is lost which is purely bad, 50% is sent to the capital which is typically purely good, and 30% is sent to other right culture/religion provinces which is questionable. Some players probably build all the buildings in their starting noncapital provinces, but I've seen a lot of expansionist players, including myself, who barely build anything in those provinces at all. Those provinces typically end up with fewer buildings than provinces conquered from the AI. Sure, the AI loves to spam crappy docks and stuff, but sometimes the AI will build useful things like workshops by random chance. As such, concentrating dev out of those types of provinces into crappy home provinces can actually be harmful. I'm not sure if the economic effects were overall a positive or negative, as I think they're close enough that somebody would have to do the calculations in a variety of scenarios for anyone to be sure. At the very least, it's certainly not a no-brainer choice like a lot of people seem to believe.
The *actual* "overpowered" part of this feature is that it lets you shred dev in uncored provinces, which decreases overextension and coring costs. THAT'S the powerful part! If the OP's changes are implemented to allow purely malicious concentration (which I hope they are), then this button will still pretty much always be a no-brainer.