IMO No its not. I have only encountered 2 doors that didn't have a key somewhere nearby, and there are a few doors that SHOULD be pickable but for "Story" reasons were given a lockpick level of 99... so yeah, its s totally useless skill now.
I feel the same about pick pocketing and "stealing" in general.. the first time I played I went crazy opening every crate looting all the things.. stealing anything that wasn't nailed down.. and it just wastes time. Seriously, you dont NEED any of those things.. plus.. and heres the kicker, if you wait until you are higher level to go around looting all the barrels and crates, there are BETTER ITEMS IN THEM THEN.. yeah, GO FIGURE. You are better off putting those points in bartering to max it as early as possible and then just "trading" for the things you need rather then trying to steal all the things..
Sneaking is good for setting up clean enemy ambush's assuming you don't use the "strategy" of picking your battlefield.. IE. setting up your ambush then using an archer to"pull" the group of enemies to where you want them.. which I highly recommend.. make them chase you to a choke point :p.
