That's true, but doesn't that happen to every other "account upgrade"? There's a limit to bank tabs, crafting professions, item stacks, character slots. I don't see why bag slots couldn't be account-wide
Some prices are strange because you can buy gems with gold. Maybe gems cost too much real money, but I think most prices are fair The only item in the shop that bothers me is the extra bag slots being character-bound instead of account-wide. I'd rather pay $10 to have all my characters get an extra slot than pay $5 for only one of them get it - and you lose the extra slot if you delete the character, aka you literally delete $5