Mystic Theurge / Cleric Domain / Specialized Wizards

[Matt2VK]

I'm a bit confused on what the Mystic Theurge ability -
+1 level of existing arcane spellcasting class/+1 level of existing divine spellcasting class.
has a effect on Cleric Domain powers and spells and Specialized Wizard.

As in do you still gain access to the Cleric Domain Spells?

What about the Domains powers? This I'm believe is a no.

What about Wizards that specialize in one school of magic?
How does that +1 Arcane spellcasting class get effected?

[Katz]

The +1 of existing spellcasting class effects spells per day, caster level, maximum level of spells you can cast, and (for spontaneous casters) spells known. It wouldn't effect bonus spells, domain bonuses, or anything like that.

[Harrison]

http://www.d20pfsrd.com/classes/prestige-classes/core-rulebook/mystic-theur ge

Specifically the FAQ/Editor's Note section:

Does a wizard (or other character that uses a spellbook), receive bonus spells to add to his spellbook when he gains a level in a prestige class that grants an increase to spellcasting?

No. The increase to his spellcasting level does not grant any other benefits, except for spells per day, spells known (for spontaneous casters), and an increase to his overall caster level. He must spend time and gold to add new spells to his spellbook.

[Matt2VK]

From what's stated, you wont get those domain spells as a extra spell slot but would the cleric still gain access to his higher level domain spells when he goes up in levels as a Mystic Theurge?

[Dragonchess Player]

You get the bonus spell slots for prepared domain/school spells. You gain no improvement to existing domain/school powers; nor do you gain additional domain/school powers.

Core Rulebook, pg. 40-41: "Each domain grants a number of domain powers, dependent upon the level of the cleric, as well as a number of bonus spells. A cleric gains one domain spell slot for each level of cleric spell she can cast, from 1st on up." (emphasis mine)

Core Rulebook, pg. 79: "Each arcane school gives the wizard a number of school powers. In addition, specialist wizards receive an additional spell slot of each spell level he can cast, from 1st on up. Each day, a wizard can prepare a spell from his specialty school in that slot." (emphasis mine)

The bonus spell slots are not tied to class level, just being able to cast cleric or wizard spells of a given spell level. Domain and school powers are tied to class level, however.

Also, as mentioned, a wizard/mystic theurge (or arcane archer, arcane trickster, eldritch knight, etc.) no longer gains new spells in their spellbook with each level. Core Rulebook, pg. 79: "At each new wizard level, he gains two new spells of any spell level or levels he can cast (based on his new wizard level) for his spellbook. At any time, a wizard can also add spells found in other wizard's spellbooks to his own (see Chapter 9)." (emphasis mine)