Is there any good reason for a spellcaster to not take the Archmage prestige class?

[green slime]

I really don't see them as too powerful (at least the 3.5 version), nor as too flavourless.

I would have preferred if Archmage was, akin to Heirophant only really an option after Epic levels have been reached. I would also have preferred more options on powers/abilities for them to take.

THe actually loss of feats on the way is a big hit. Personally, I wouldn't take Archmage, I'd prefer Loremaster myself.

 

[Capellan]

Another thing to remember is that 5 level classes (comparatively) nerf your BAB and save progression. It's only a small thing, but a Wiz5/Blah10/Archmage5 has a BAB of only +9 and base Fort & Ref saves of only +2, plus whatever is gained from "Blah10" (so either +5 or +8)

Also, the fact is that, as powerful as the class abilities are, you do have to give up spells to get them. They aren't "free".

And let's not forget that it's kind of boring, thematically. Acolyte of the Skin or Alienist is far cooloer, for instance

 

[Nightfall]

Archmagery is fine if that's what you want to focus on. But there are some much cooler Pr-classes out there, like Animator if you're a necro-freak, or Crypt Lord. Then there's always my personal favorite for sorcerers, Blessed of Mesos.

 

[Black Knight Irios]

I think that depends on the WIZ what PC he will choose, sure Archmage is really pretty good and it doesn't matter actually what other PCs you take as long as the spell progression is straight. You can have a WIZ/Archmage, a WIZ/Red Wizard/Archmage, a WIZ/ROG/Atcane Trickster/Archmage etc. some might make you even an epic character. Some WIZ might feel more comfortable with other PCs that are more special, like Elemental Savant or something else...maybe the WIZ will continue his way without any PC at all and I think there is nothing wrong in doing so and it is up to each player to choose what he will do with his WIZ.