MerakSpielman said:
It's generally considered to be overpowered becuase it eliminates the primary penalty of being a high-level multiclassed caster.
To be precise, what it does is to make that
completely unworkable archetype somewhat more playable by bringing it nearly up to par with its single-classed equivalent.
I haven't seen it in actual play, but it seems that it would be a very powerful spellcaster, but limited skill points and bonus abilities make it much less useful in other respects.
IMX(extremely)HO, the MT is not a
powerful caster; it is a
versatile caster. An MT is not a spotlight hog or a game-breaking DM's nightmare; what having one in your party does is make encounters, especially the third or fourth daily encounter out, substantially easier for the party overall. In many ways, the player of an MT is likely to be quite bored (as the one IMG was); it's a better class concept for a cohort, really, since it spends the vast majority of its time and resources buffing, healing, and providing utility spell capability to the average PC party.
Essentially, Cyri', think of the MT as a wizard with the following benefits:
1) two domain powers (possibly useful, as long as they're not level-dependent)
2) +6 hp
3) cleric spellcasting (essentially, double the spell slots per day)
In turn, the MT loses the following:
1) 3 feats (including Practiced Spellcaster)
2) Access to other PrCs (an opportunity cost)
3) Access to the top 1-2 levels of spellcasting
4) Higher-level wizard spell slots
While this may SEEM like a good deal, IMHO it is not. A wizard typically lets fly with his highest-level spells in any vaguely-challenging battle, making his 4-5 best spells disproportionately important. In effect, the MT trades those spells for lots of utility and healing cleric spells, which is good for the party from a long-term resource perspective but does nothing to secure an immediate tactical advantage.
In short, the seriousness and uncertainty of the tradeoffs indicate that the MT is balanced. It is CERTAINLY not overpowered.