They aren't a waste at all! The initial feats are some of the best ones printed (especially the more stat-restricted MP ones, Battle Awareness is great), and spending feats to branch out and expand your versatility (say, a Barb becoming more of a defender by taking Fighter powers) is a fair trade. This helps prevent jacks-of-all-trades from being too powerful, and from losing their ability to cover their main class's role (only half your total powers can come from your multiclass, which is a fair limitation).
Multiclass Paragon Paths are also fantastic-- plenty of Wizards are well-advised to go Divine Oracle, and a Paladin with Pit Fighter is friggin' scary.
Paragon Multiclassing is weak, true, and I'd give it a couple of houserules to improve it. But at-wills are the cornerstone of a class, and are the basic method by which they accomplish their job in combat. Letting a class take another's A/Ws is very dangerous balance-wise (imagine letting all classes take Twin Strike), so it needs to be heavily restricted.
But the best evidence that 4e's multiclassing is awesome is the Wizard/Cleric. Once a total trap--even with Mystic Theurge--now well-balanced and even optimal for some builds. That's progress.