I think its bad idea.

Better would be to make mahjong more interesting for players so there will be more people in queue. Like i said in another mahjong thread.
- Add good tutorial - so more players will have it easy to learn to play.
- Add better rewards - like mgp for every game.

There are things that can be improved, so more people will enjoy this game.
If people will be able to play ranking matches against NPC, queue will get even worse than it already is.