Yeah, the fact that they use a surge is pretty crazy. Healing potions really are no longer magical, they're just Red Bulls. I can see a pretty common house rule being that players have infinite surges, or that potions don't use surges.
6 hours of rest magically heals all wounds, thus most of the time potions aren't needed. However if the adventure has a time constraint, having a daily limit on surges does exactly what you've said, places the DM in a position of either boning the players or having to change the adventure. All because of some silly new limit that had no need to be imposed. Healing surges really are a pointless mechanic and they're very immersion breaking. They do very well at simulating kid's cartoons like Naruto where one frame he's dripping blood and the next he's perfectly healed up and his cloths are no longer ripped, but they're complete crap for making one feel like one is playing a fantasy character.
Wow, tell us how you really feel about it.
Healing surges are a game tool for resource management. They replace the everpresent 3.x wands of cure some wounds. Instead of running out when you run out of money (i.e. just about never), healing surges run out daily. The overall feel of healing magic in 4.0 is not that different than 3.x. It's simply broken down per player so each player keeps track of their own "wand charges" instead of the cleric, and healing actions are less of a drain on combat actions.