It's not hard to build a trip monkey in 4e. Just play a polearm fighter that has the footwork lure at-will and the polearm momentum feat, and you have a fighter that effectively has a tripping at-will.
Exactly trip builts are easy in 4E and there are many of them.
Disarm does not fit 4E paradigms. It fits 3.5 were every ability had a hard counter. Antimagic and high SR tramples spellcasters. Excessive DR tramples physical damage, disarming tramples weapon users, immunity abjurations negate everything else. In the end a well prepared group fighting an enemy that has taken some time to observe them has complete immunity to whatever the opponent can dish, and he has the same, and everything is judged on who can dispel the other quicker. And if something cannot be dispelled then a player may very well end up a cheerleader for the rest of the fight. 4E takes this to the opposite extreme where it is relatively hard to actually make a dent in the opponents offense by careful preparation (unless you spend your days making potions and elixirs), but I for one prefer this end of the spectrum.