Here's an example why encounter powers suck for story :
You have a big battle, and a warlord, or cleric, or bard, and they have encounter powers that let you spend a surge +1d6, or +3d6.
The battle's over, you wait 5 minutes to heal your comrades so they can get the "free" 1d6. Oh, but you tell them, "don't surge up, because it's wasted surges". Why? because those who need healing, but can't benefit from your limited per-encounter resource (healing/inspiring word) right away, should rather wait another 5 minutes for their turn to get another, "fresh", 1d6 for free. Essentially, breaking up the post-battle into 5 minute chunks of healing. It sucks. The DM at our table groaned when we did this...and if he tried to say "no", it was unfair to the leaders who had taken that class feature, especially if they spent feats to boost them, or bought magic items to boost them.
Much, much better to allow people to spend it all right away if they need to, then be out for the day sooner, than have the day cut up into neat-o 144 divisions (5 minute chunks of the day).
Being able to cast something 144 times a day is no more realistic than casting it 5000, or 5 million...because after a couple dozen, who's counting anyway?