This sort of thread is exactly what bugs me about our 4e conversations.
The designers say "abilities will be per encounter."
Everyone flips out about "how do we define an encounter?" and "we can get longer buffs by stretching the encounter!" and "our DM can screw us by defining an encounter item by item!"
Except we already have a book which is built entirely around per encounter abilities, written by the same designers as the designers of 4e, and which showcases three separate ways for per encounter abilities to function. Its called Tome of Battle.
1: The Warblade recovers all of his abilities with a single standard action, OR as part of making a standard action or full round attack.
2: The Swordsage recovers all his abilities after one minute without combat. He can recover individual abilities with one full round of concentration.
3: And the Crusader (correct me if I get this one wrong) gains his abilities at the onset of hostilities as a gift from his God, and refreshes them whenever he uses a certain percentage of them up. I believe they also clear and need refreshed after one minute downtime, but I could be wrong on that.
Each one of these addresses the complaints about the definition of "per encounter. The Warblade handles things by not really being a "per encounter" character. His abilities are infinite use, with a mechanism that requires him to spend one round suboptimally in order to refresh them. If your Warblade has ONE ROUND in which he isn't fighting, he can have all his abilities back. All he's got to do, in game, is a weapon salute after the last round of combat.
The Swordsage is probably the most "per encounter" of them, and his abilities aren't strictly "per encounter" either, they're timed, but with a really, really easy to remember and really, really easy to adjudicate timing system. Instead of multiple abilities refreshing on multiple rounds, all of which need to be tracked, its "one minute of no fighting, get everything back, or one full round action to get back one." Bam, problem solved.
And finally the Crusader, who has a quirky, beloved by some, hated by others mechanic for refreshing his abilities, that happens to also use the "one minute downtime resets you" mechanic.
None of these characters have the problems people are bringing up.
Its possible that all of these lessons will have been unlearned and forgotten in the design of 4e, but I wouldn't rate that possibility very high.