Not sure that this is a bug or not, but oh man, this is interesting. So, since cards now stay in your hand until their effects resolve, you can now end up discarding a card you're going to use when using the Exiles and their bizarre random discard mechanic. The thing is, the card still goes off. Say I use Ritual master with Recycle being the one card in my hand. Ritual master is set to go off first, and he does, ditching Recycle. Recycle then activates and does its effect, putting a card back into my deck and drawing one for me. This also means that if it's an ability with Exile, you will not only use the card up this turn, but if it has Exile, you can use it again next turn by paying the Exile cost. This means that Reckless Abandon can be used with any ability card to effectively use it twice and all normally Exile-able cards can be used twice in-a-row when discarded other ways if the RNG cooperates. Yes, I know... RNG. But still. Just remember, you have to have it get discarded before it would normally activate.
Remember though, this is probably a bug. Would be fun to pull off two uses of Descension with only one card though, or to use Spontaneous Combustion two turns in-a-row and wreck the playing field if a bit randomly.