Lets put it like this. It will cost you regardless since you have choosen one level of rouge already. (Lost the last extra attack) but if you make the best of your rouge levels you can take advantage of the sneak attacks and the avoiding to step into deadly traps all the time to compensate, and with magic item, you can use magic items and scrolls without armour penalty.. Ainīt NWN nice??
I would either go for 3 levels of Rouge or perhaps even as high as to level 5 in rouge. I have one character currently level 9 fighter and level 5 rouge, and he is strutting around in his full plate +3 chopping heads and limbs and making dragons into handbags for sell