Egads, I hope no one ever creates such a thing. It would just be wrong. Not that the truly powergamey would use it, though - see below.i think he meant a class with arcane + divine + psionics
Regarding the hypothetical brokenness of the OPs class, I think it's not. Actually I think that aside from cool flavor it's not strong. What you get is lots of spells per day, and a good combination of flexibility on-the-fly with flexibility in situations where you can plan ahead. However, you're still limited to arcane only. In contrast, Mystic Theurge gets access to both arcane and divine magic.
Many people's initial reaction to the MT is that it must be horribly broken, since it gives you two full spell progressions at once. However you will be behind in caster level, and you run into serious MAD. Furthermore, you can still only cast one spell at a time, no matter how many you have per day.
I, too, am curious as to how this class could abuse Persistant spell/Quicken etc any more than a normal caster.