None whatsoever. That's what I'm getting at. We already have menu-style class features. Why do we need feats too?
Improved Initiative is an argument for feats as a separate entity, I admit... but it's also an argument against, because its impact differs by class. It's an okay feat for rogues, and mediocre to bad for anyone else; in effect, it's a "rogue feat" masquerading as general. That's not to say the issue couldn't be fixed, but it underscores the challenge of balancing such things across all classes.