Dont forget the difficulty, they would have to be more difficult. Mainly i think they would be for people looking for a challenge, not for grinding and if we keep part of what the OP said, it could be a limited number of games per day (if this is the case, then a higher reward would be more reasonable).
But then again all of this is hypothetical and I dont think zanz has shown any interest in making another higher difficulty opponent. (might be wrong about this)
