I'm starting up a campaign and reading through this I find that there is no real downside to chosing a domain. Specialist wizards give up a list of spells to gain an extra spell slot and +1 caster level. Domain wizards just basically get a free spell at each level and a +1 caster level to cast it. It's not too overpowering, but am I missing some downside somewhere? True, it's not as powerful as a specialist, but compared to a base wizard, it's all good.