Summary: replace the current exponential rise in resurrection costs with a sigmoidal gompertz function type response.
This beta has a lot of new features that I like, including the option to help revive fallen allies if you truly want to continue with the group of friends you've assembled.
However, the rate at which revival energy cost rises is pretty high- 2^n energy adds up fast, especially against enemies that can cream you with a single blow. This creates a game design quandary: it's good to keep the cost of healing high (so as to encourage skill and planning when going for lower levels), but if the cost becomes sky-high too fast, people will quit the level altogether instead of paying. That makes it unattractive to players, and in return, keeps OOO from getting the maximum benefit out of this feature.
Instead, might I suggest increasing the cost of revivals according to a more gentle function? I would propose a sigmoidal response, such as the gompertz function ( http://en.wikipedia.org/wiki/Gompertz_curve ), which has the following desirable characteristics:
1. A player with few health bars starting out gets a "grace period" of a couple of cheap revivals (price rises very slowly)
2. After heavy revival use, the cost jumps more dramatically, to ensure that repeated revivals are priced outside the reach of all but the most crazily determined players
3. Once some threshold is reached, the revival costs again level out- hence, the most determined players can afford to keep reviving for a long time, which in turn keeps them shelling out long after the current pricing system would drive them away
As someone who has spent 5k on a full party rez I support the notion of a hard cap on rezzes.
That said don't make it too low. Maybe cap out at 500 per person?
All I know is. that's where most of my money has gone since being implemented. haha.