The things my group has experimented w/ are along the lines of what Midnight_v suggests. Although they are probably a little less extreme.
Hmm... maybe but there's nothing extreme about what I suggest really, its kinda about balance in some aspects.
The sunder thing was a joke, obviously.
Fighter really used to be my favorite class and one of the first things I noticed was the problems that were talking about, how Improved trip was good because it made target easier to hit and netted a hit.
Though things like feint and disarm, were really bad comparatively, feint because too much could happen before that next attack.
... and disarm because, well a good portion of the critters don't use swords, that went for sunder too (once I realized you couldn't sunder armor, which was pretty quick) but people had other issues for that.
Bullrush really sucked as battlefield control and there weren't enough uses for it, and so when dungeon crasher showed up, years later, I thought what everyone else though "Bullrushing finally has its day"
Rarely do people trample or overrun because the effects don't seem to do enough, and lots of the time its the demense of monsters, and/or Mounted Warriors, so they don't see much play because of that as well, but yeah it just has to be worthwhile somehow.
The simplest way to do this is to equate the other manuvers with improved trip or alternatively with Dungeon crasher.
The issue as to why those get neglected is because they're not very efficient. Efficiency in this case means putting you ahead as a warrior in either the damage race or the action race.
Disarm is just so limited because more than half the monsters use natural weapons. . .