So I understand the leaver system is in place to stop people frustrating other (human) players, but why put in a penalty for leaving vs A.I? Just seems completely bizarre. The times I left was when I knew I couldn't win so I saved a small bit of time by leaving (of course I would not do this vs other people though).
I actually agree with the original poster. Matches with 2 people in them give "in game experience/knowledge" to the 2 people playing them. If you leave the match, then you're essentially "voiding" a piece of experience which could make their strategies better/worse. Matches with 1 person and an a-i give the human "in game experience/knowledge", therefore leaving doesn't hurt both parties.
It's annoying, sometimes I just want quick games to try out decks or fulfill certain missions, doing some of the missions is extremely long winded vs quite a few players because either they purposefully stall rounds (waiting till last 5 second and play card) just to annoy you, or they just timeout the battle when they are about to lose.
Thankfully this doesn't happen too often, but it still sucks the Joy out of the game for me, and so this is when I switch to a.i. battles since they have 10x more sportsmanship than the above players.
I've got to say though, the A.I. in this game is very strong, probably the best A.I. I've seen in any card game and sometimes they do completely unpredictable plays. There are times when they make really stupid moves though (for example using all pills on first round for only 4 damage).