Originally posted by drnuncheon
Interesting that you bring Spellsword up, since that's what I generally compare Arcane Trickster to. Note that Spellsword only advances in spellcasting every other level...it basically works out close to if you had advanced equally in Ftr and Wiz, and then adds some (very nice) gravy on top of it in the form of the armored casting. I think the Spellsword is balanced about right, and the person playing one in my game doesn't seem to think it's underpowered...but that would indicate that the Trickster is overpowered, since it's as good as 10 levels of wizard plus 10 levels of rogue, and not 5 of each...
Well, first off, you emphatically do
not get the power of 10 levels of rogue as an Arcane Trickster - you only get 4 skill points per level, which is the skill points of 5 levels of rogue. You also only get the BAB of a wizard, so a Rog5/Wiz5/ArTr10 is still only going to have a +10 BAB, the same as a Wiz20. You also only get d4 hp's, so you're going to have significantly fewer hit points.
You do get the full sneak attack progression of 10 levels of rogue, but you're much less likely to use your sneak attack, as getting up in combat and flanking is going to get your ass kicked quickly. So, you're only likely to get much use out of your sneak attack in the surprise round and the couple of times a day you use the impromptu ability (and twice a day of impromptu sneak attack is hardly unbalancing, considering how often normal rogues can sneak attack when they flank). You also get ranged legerdemain, which is a nice ability, but nothing to get excited about.
The spellsword, though he doesn't get the full spell progression, does get other benefits. First off, whereas with the Trickster, you're stuck with being either a Rog5/Wiz5 or a Wiz6/Rog4 in order to meet the prereqs, that's not your only choice as a spellsword. You could be a spellsword as a Ftr7/Wiz3 or a Wiz9/Ftr1. This opens up some options to the spellsword that aren't available to the trickster.
The spellsword also gets d8 hp's and a better BAB (though I would have liked to have seen this one be one of the rare PrC's that goes from +1 to +8 rather than +0 to +7). He also gets the ability to cast in armor, which is
much more generally useful than any of the Arcane Trickster's special abilities, and the main reason why he only gets to go up every other level, IMO. With 10 levels of spellsword, it's possible to cast without the chance of failure in chainmail, or with only a 5% chance of failure in plate. That's a
huge advantage over a Ftr10/Wiz10. On top of that, he gets the channel spell ability, which is nice, a bonus feat, and what is essentially another free feat in the form of the spellsword cache.
To sum up:
Compared to a Rog10/Wiz10, a Rog5/Wiz5/ArTr10 has fewer hp, worse BAB, fewer skill points, and 1 fewer feat, but better sneak and 5 more caster levels, plus a couple of minor special abilities.
On the other hand, compared to a Ftr10/Wiz10, a Ftr5/Wiz5/SpSw10 has more hp, the same BAB and skill points, better saves, and the same caster level. He does have 3 fewer feats. However, he can wear armor. He also gets a few minor special abilities. It could also be argued that this isn't the optimal configuration for a spellsword and that, depending upon how you want to play it, either a Ftr7/Wiz3 or a Wiz9/Ftr1, or some other combination, would be better.
As I see it, these work out to be about the same in the long run. The arcane trickster is weaker than the straight multiclass in most areas, but gets more spells. The spellsword is the same as the multi in most areas, and gets to wear armor. Both of these represent, IMO, a significant improvement over the plain multi. However, neither is particularly unbalancing.