This stuff is a huge pet peeve of mine. Talking about classes and races in theory is fine, but people seem to only dissect classes in a vacuum with no regards to the setting at all. Is the mountain dwarf a bit better in certain situations? Sure, I'll concede to that, so then you have to ask yourself. Why does there exist a dwarf wizard in the first place? The vast majority of dwarves are going to focus on martial classes because they have synergy with the bonus. I'd imagine in just about any world (7dwarves taken as is) you aren't going to see dwarf wizards often. Sure you can make your special snowflake and go against the flow but the big question is, why would you even want to? These class theory threads who prove dwarven wizards are the better wizard usually implies people saying "Why create a high elf wizard if the dwarf wizard is better?". The thing about that argument is self defeating, why would you play a dwarf wizard if dwarves make the best fighters?