I sometimes regret not picking Fealty due to the Nobility policy. +100% Production towards Castles/Armories and an easy, fast +1 Happiness per city is great. +100% Production towards two buildings, means, in practice, it's similar to getting one of them for free. If I had a policy that gave the production equivalent of free Armories everywhere (or you can devote that Production to a University or something) I'd say it's pretty good. +1 Happiness per city (this alone is pretty good), and +3 Food, stacked with the Monastery's +3 Food and the scaler's +1 Food for a total of +7 Food per city from just two policies is great imo. Burghers certainly pulls its weight, if you have semi-permanent WLTKD, it's +15% Production towards everything and double Border Growth (great as Authority) which is pretty good. +5 Food/+15 Defense per city is strong too imo.
The issue I have is with Divine Right/Serfdom...Divine Right is one of the weakest policies in the game and Serfdom isn't far behind. I think, if Fealty should be buffed, it's these two policies.