This came up in another thread, and I need to check my memory since it's been literal decades.
My memories of 3.5 was that the player-facing options in the splatbooks really added power when someone was trying to optimize. Especially some prestige classes. This isn't saying all the material was more powerful, but some of it definitely could be either used or cherry-picked.
Someone else mentioned that all the most powerful options were in the core books (so that includes the Mystic Theurge and other DMG content, not just the PHB).
I really remember the splatbooks adding to power creep, and that someone intentionally optimizing a character with full access to the splatbooks would be able to create someone significantly more powerful than if limited to just the core books.
What are your thoughts?
My thought is that the question asked here, and the statement to which I responded, are two different things. Or, at least, I think a LOT of the people who respond to this question are not answering the question you intended to be asking.
Because reading this, it sounds like: Is there ANY amount of power gained by ANY characters by using splatbooks? And of course the answer to that is "yes" and should be "yes". Anyone who says "no" is either not entirely sane, not thinking logically, or having an agenda.
But the thing
I said, and which is
not what is asked here, is that MOST characters DO NOT get meaningful power from MOST options in splatbooks. Like the overpowered things are, at best,
maybe 10% of the total content. You have to trawl through a dozen different books to assemble enough things for it to be more powerful than options from the PHB. Is it possible? Most certainly! The Planar Shepherd actually manages to out-do straight Druid, for example; it is one of the
only prestige classes to do so.
That's not the same, though, as saying that most splats were plagued with massive power creep, which is the claim I originally responded to negatively.