D&D 3.5 doesn't work without knowledge checks. There are lots of monsters that have abilities that will destroy a party that doesn't expect them, and that aren't immediately evident from their description.

In a high lethality game like 2nd end and earlier, you can get rid of knowledge checks because if the mystery monster kills a character it's no big deal. In a more forgiving game the characters can take a few rounds to make mistakes and figure out the monster's abilities, and there is a sense of discovery. D&D 3.5 is neither of those games: combat is fast, characters are detailed and take effort to create, and "discovering a new monster" often means a character will die.