I mistakenly picked the "two-handed style" weapon talent for my rogue. I unfortunately noticed the mistake a level or two later and do not have an old save I can revert back to. Is there anyway to change talents once they have been selected or am I just stuck? :/

you can use the IE mod to lose that skill and add the one you wanted instead

You're now officially part of the ragtag team! Durance would be proud to call you field commander. You're one of them now. 

you can use Console Commands

 

Though keep in mind it disables steam achievements

you can use Console Commands

 

Though keep in mind it disables steam achievements

 

The IE mod allows the use of console commands without disabling achievements.

 

Mod here: http://www.nexusmods.com/pillarsofeternity/mods/1/?tab=2&navtag=http%3A%2F%2Fwww.nexusmods.com%2Fpillarsofeternity%2Fajax%2Fmodfiles%2F%3Fid%3D1&pUp=1

 

List of console commands here (31 is of special interest, read those): http://rien-ici.com/iemod/console

 

Although the mod says it doesn't work with the current version, it does. They just hotfixed and didn't change much, so the mod works fine.