So Im working on a humanoid Wizard and wanted to put in the Simple Wizard Class template to bolster his ability to be this intense, well gifted wizard that will appear in the campaign from time to time. Im wondering if by RAW, adding the Wizard class levels and the Wizard like spellcasting given by the simple class template would just increase the number of spells he could cast or would it just change his effective wizard level and give him a higher than level spellcasting ability?
Any insights guys?
The simple wizard template, like most simple templates, is a shortcut for augmenting a creature--in this case, adding wizard spells and abilities without having to do a bunch of work adding the levels by hand and recalculating everything. It's a GM-expedient alternative to actual wizard class levels, not a means to augment an actual wizard. What you're describing is essentially a gestalt wizard/wizard. If that's your bag, go for it, but you're in GM fiat territory--it's all up to you.
It sounded like a wizard/wizard gestalt to me as well. But it also sounds like OP is the GM, so if it's what you want to do, then I say but the ticket and take the ride.
As per the rules, though, I would imagine it either straight up does not interact at all and isn't allowed... Or, it would require level adjustment just like as template for a playable character. Given it's a simple template, probably one level less for that adjustment would be my guess.