How you "fuck up" Samurai build? Samurai already starts with whirlwind so this is just fast whirlwind + samurai style reach = 2 feats. Is, according to you, samurai a feat starved class and this is about full Archmage (1 feat per 3 level)? Because otherwise i don't see the problem? Not saying that you are wrong just trying to understand. If not feats that leaves the weapon issue, making two weapons for one character is not economic, you are probably right here.
Both.
With the original rules (Archmage) you only get 10 feats + starting ones depending on your race.
It's just enough for an attack/crit focused samourai + saving throws feats.
Arguably, you don't need more crit chances but you really do, because even with skewer, the toughest enemies have high AC and getting a roll > AC +5 isn't a given.
Gold and crystals are also an issue.
Now, if you play on baby mode, sure, what the hell, pick all the feats, max attributes, reduced enemy levels, reduced enemy ini.
Well, you don't even have to plan your build, now, do you?