Alternatives to expertise actually wouldn't be so bad if done properly. But they shouldn't get special stances like monks for sure. When I think alternative uses to expertise I'm thinking get rid of the default bonuses and replace it with something "flavorful". Like say you get 10% elemental protection but 10% physical elemental vulnerability while activated. (Just a crude example)
Of course this might not even be possible without some extensive tweaking.
Of course this might not even be possible without some extensive tweaking.