Hills I'll defend to the death (as opposed to those I'll merely defend to the serious injury
):
--- The concept of ranged healing simply should [edit] not [/edit] exist unless it's being done by a deity.
--- Fail means fail. Not succeed with a cost, not fail but move forward, nor anything else other than you simply flat-out fail, or worse. To succeed with a cost you first have to succeed, rather than fail.
--- "Nothing happens" is a perfectly viable result for those great many action declarations where something might have happened, but didn't.
--- In the interests of balance, pretty much every benefit should and must come with some sort of corresponding penalty somewhere else.
--- Corollary to the last: there is nothing wrong with penalties be they minuses to hit, species-based stat penalties, or whatever.
--- PCs are first and foremost inhabitants of their setting and should - and must - reflect that, in that PCs and NPCs are at their root the same things.
--- A creature's stats define the creature and stay constant regardless of its surroundings or who-what it is encountering at the time. No minions.
--- Common sense and believability win out over nonsensical rules every time. No, you can't trip a snake or a gelatinous cube. Fireballs are round, not pixellated. Nothing ever has to snap to the grid. Etc.
--- Rushing the game's pacing produces a poorer experience. It's not a movie with a limited run-time, nor does it have any requirement for always-on action; it's an open-ended pastime where there's always next session in which to do whatever didn't get done this session.