Ok, this is like only an opinion, but I rather like having the -.+ mechanic. I like how it forces me to consider the down side of a treasure, in order to get at the other side of the choice. Currently the only draw back i see, is that it is possible to go back a level and kill re-spawned enemies to raise health instead of making the difficult choice.
If that re-spawn could be delayed until the end of the level then these choices would not seem to be useless, but useful, just with a difficult weighting of the drawbacks versus the benefits.
From plus or minus 20 to 80% ? Or is that range to small? Or too much?
Certainly the ranges now, being very extreme really make the choices hard to make, if i know that i have to lose most of my health for a devasting ammo boost.
Actually, to be honest, i rather like the extreme way the treasure chests are now. If we make them 'reasonable' then honestly, it makes it less extreme and less fun.
At least that is my opinion,
-Teal