I very strongly agree with the notion that fighters seem to be capped at the "3rd level fireball stage", whereas the casters get powers to go above and beyond. It's a matter of content and the spell lists are vast and multi levelled, whereas feats get a lot less space.
When a fighter player gets access to more books, like "sword and fist", then the extra feats help, as do extra prestige options, but it always seems that in the initial rulebook, fighers have to make do with living in a third of the feat section. One extra page, with a new tier of melee feats, would go a long way towards evening this out. It's like people forgot that fighters beyond level 8 or so even exist.
It is worth noting, however, that any changes to fighters must be carefuly balanced against barbarians. Knockback, for example, was mentioned above as being desirable "battlefield control". Barbarians pay a hefty cost to get this, both in rage and the fact that it is a swift action and thus prevents any other use of rage powers. It's a really big thing for the barbarian to do, so if the fighter gets it with more utility, you will find that barbarians all reroll as fighters (especially if their other powers are taken in the same way).
Currently the barbarian thrives on being able to do the funny things a warrior cannot...that difference is a very fine line and the barb could be very quickly made obsolete by even the slightest changes. I am hopeful that the current rage and rage power review that Jason B is undertaking will improve barbs and thus allow fighters to "move up" a bit in power terms.