in kotor 1 the underwater manaan part,real boring
the taris sewers and the undercity i didnt like either
the loading times in both games were annoying
kotor 2 i thought dantoonie was really dissapointing and korriban was too short there should have been more to do.
i also really didnt like kreia and how she forced her way into your party at times.
other than that i cant really think of a lot except for the k2 ending and all the missing content in it.