With Courage, your opponent can see its ability and must guess how you're playing it. With Reprisal, they have to take a guess that you'll even play it that turn, but they could also play a card that makes your Reprisal a weaker move (Nistarok for Mechakolos) or a riskier one (Edwin for same).
Courage cards can be played off turn as a surprise. Reprisal cards played off turn loudly announce their lack of ability, but could still be played in a surprising way. It makes an interesting mind-game, but only if the ability is worth the limitation. I think it's appropriate that the first card with this condition is a GHEIST imitation of a Nightmare; both clans focus on scaring your opponent with what they could do and obfuscating when they'll try to do it.
A Flip-flop condition? Could be interesting, but probably too much text for most people. Could get pretty crazy, even more-so if the two conditions weren't even opposites (and Stop were added to the mix). Things like Courage: +1 Power/Revenge: +1 Power or Power +1(Stop: +4). It's a fun idea in theory, but in practice, less is more and unconditional will always dominate.
Considering Frozn, the staff has probably given that some thought, but like Frozn, players may just write it off as a gimmick clan and stay with any-turn bonus clans. Combined with Myeltd's idea, we could have a mind-game clan that doesn't suffer from vanishing bonus, but we wouldn't get that ability-or-bonus choice.
For those who don't understand the problem with Ambre- they should see the thread: Cards that deserve penalties/Cards that don't deserve penalties Post 33 makes it amusingly clear. It's admittedly a Tourney thread, but the same logic justifying Ambre's 10 point penalty can be used to argue why Ambre dominates in survivor. Ambre has her place in Survivor, but she still removes enjoyment from the mode for players who want to think about how they play- to use Ambre there is little thinking required.
Ambre is such a force she allows easy victories against all hands not specifically designed to counter her. As said, nothing could be better as an Ambre counter (besides using her yourself or avoiding survivor) than cards with Reprisal abilities. In providing more Ambre counters perhaps people will think twice about using that stupid card! If they do use her, at least the rest of us will have a method of dealing with her other than pot luck and vast cash reserves...