Sure you didn't play Oblivion?
With maxed first Dual Wield spec(the top row of abilities) you can dualwield longswords, until then you need to use daggers and possibly shortswords(do they even exist?)
The assassin talents apart from Mark of Death doesn't work at all, they are totally broken. Duelist is a way better option currently :x
really? i havent taken the talents yet and i guess i wont either that sucks
Alot of other specs are kinda broken too, for example Reavers 4th talent doesn't work at all, the same goes for the Dual Wield spec 3rd talent(a bleed when you backstab/crit - doesn't work).
On my second play through lol
Got the final party member to unlock the achievement
Warning major spoiler!