Can I take the Tight Fit feat for my Medium character, for use when he is wearing his Large power armor? It says I must be Large or larger. Insofar as I'm aware, you can still take feats even if you only sometimes meet the requirements; you just can't use them unless you meet the requirements.
Insofar as I'm aware, you can still take feats even if you only sometimes meet the requirements; you just can't use them unless you meet the requirements.
You have to fully qualify for the feat in order to take it in the first place. You just don't lose it automatically when you lose a prerequisite.
I think that was done for things like spells that would change features of a character. A character that has Tight Fit that gets affected by a spell that shrinks their size doesn't have to scratch off the feat on their character sheet and then somehow re-acquire the feat again later. Especially since the spell would only be temporary.
Now, as a house rule I am all for this idea of being able to take feats that you don't always meet the requirements for. Both being able to select feats that you only sometimes meet the requirements of or only meet the requirements when you have certain equipment. There is even some precedent for that in feats like Sky Jockey that only have an effect when you are using certain equipment.
Now technically Sky Jockey doesn't violate the actual rules since it doesn't have requirements of using the equipment. It only requires a skill rank. But the feat is similar enough to what you want to do with the actual character that I don't see allowing Tight Fit as an equipment improvement feat as unbalanced.