You guys are overlooking a few key components. For one, no, if you are not going to invest heavily in Finesse, then sneaking is probably not going to work out for you.
I personally like playing a sneaky character, and in this game it is still very much viable--albeit more so at the later levels, as stated.
With sufficient skill in Stealth, at least 3 points in Detect Hidden, you can manage enemies' sight lines pretty well. Now, sometimes you WILL run into those groups where the devs were specifically messing with rogues by putting 2-3 mobs sitting gazing soulfully into each others' eyes (so if you're sneaking on one you're walking right in front and center to the other), but even these can usually be dealt with by using the terrain, rolling, and good timing--you stab one guy right as his boyfriend is realizing there's a problem.
Then there's Smoke Bomb. This adds another element. Now you can sneak one, wait until the rest circle up around you, and bomb. It stuns them, makes you invisible, and puts you straight into sneakcrouch. With good target picking, this can be an opportunity for another stab--or even two. Since it clears all awareness in the first half-second or so (not just makes you invisible while leaving all threat/aggro/awareness on the target, like many games do, so that when you're no longer invisible they're jumping your face again), sometimes you can even work it like thus: Stab one, piss off others, bomb, stab one, stab two, roll out (usually helps if there's a corner or obstacle to dive around), and the rest wake up, shrug, look at the bodies, and go about their merry way. By then if you've picked your targets well, you've eliminated all the sneak-impossible combinations, and can chain-kill more or less at your leisure.
And if push comes to shove and you can't sneak everyone, hey, Finesse builds are far from helpless. Wade in with Faeblades and make them pay.
And if it's someone big and burly (like a crowd of Jottun), you always have the option, if you've cleared your approach, of killing one and bailing. Sneak, slit throat, desneak, sprint out, get around a corner, and resume sneak. If you know the right distance/sight lines, oftentimes you can clear threat this way--even work back around and kill more while they're all strung out in a line walking back to reset.
And finally, if you even mildly like alchemy, I have 3 words for you: Minor Phasewalk Potion. It will give you the same undetectable status, for about 6 seconds, with a 10-second cooldown. So they won't give you permanent invis, but 60% uptime is pretty respectable. Theoretically you could even time a Phasewalk, Bomb, Phasewalk, to stay stealthed for 18 seconds (though I've never actually had to do so)--and if that's not enough time for you to get out of anything that isn't an arena-style boss fight, then maybe sneaky isn't the playstyle for you. It's made with reasonably common mats, too, no Essences of Fate or anything crazy like that required.
And in closing:
100k sneak crits (with a prismere dagger, sure, but pretty lackluster components otherwise) are pretty hard to argue with.