Don't have the chain admins too much power

No. The most harmful thing chain admins could do is trying to earn FairCoins by increasing the transaction fee for CVNs they control (the upper limit of this parameter is 0,2 FAIR per standard transaction). However, if it became known that more than five chain admins wanted to break out and not follow the decisions of the assembly, a new wallet could be issued, re-establishing the rules decided democratically. FairCoin users would need to change their wallet, though, but this is the way all other cryptocurrencies patch any severe or unforeseen problem which may occur during their lifecycle anyway. With chain admins being able to fine-tune some parameters with the move to FairCoin, we likely will never need to change the algorithm again, as they are able to fine-tune operational parameters.