D'karr
Adventurer
I also think it is possible to make an at will maneuver system, provided the penalties, bonuses and advantages/disadvantages are thought out.
This is exactly my point. What makes spellcasting "difficult", in a system like 3.x and PF? Why should martial maneuvers now have to "balance" penalties, bonuses and advantages/disadvantages?
My point is that we have been conditioned to "think" that these things are so difficult to do that the mechanical options those games provided are statistically less worthwhile than "I attack with my sword." So the system baseline "discourages" the use of the maneuver (provoking AoO, etc.) Then the system provides "outs" to make the maneuvers more attractive/possible - eliminating the disadvantages by spending feats. At that point the players has invested so many resources that the maneuver is "way more attractive" than the baseline. That is where you start to see the spamming. Which was the case with trip. The martial character becomes a "one trick pony". So the system then attempts to balance in the other direction, by making things very situational.
The AEDU structure is not perfect, but it went a long way to address the issues (feasibility of maneuver & spamming).