There is nothing wrong with hide/spot. Characters like Emanuel, a Druid heavily invested in spot should be able to detect everyone.
However the cosmo feats should be removed asap before players get too attached to them.
- they offer no rp incentives. You do not need to have more that 16 in perform for example. If you need to, multi class.
- they promote even more mix-maxing
- it detracts from a class/build uniqueness
- it simply is a power creep. Easy access to umd for classes that would lose a lot otherwiseie rangers losing spell progression, fes, epic feats - barbarians losing dr, epic feats or simply having more multiclassing options
- finally it goes against some changes(nerfs) that happened not too long ago. What is the reason for nerfing the ac of the dragon form if a Druid can pick cosmo tumble instead of armor skin for a +1 ac in total or allowing easier access to umd shenanigans for everyone
TL;DR the cosmo feats is a silly(sic) implementations