I dunno about a shift, but good lord, Tieflings and Warlocks really seem evil. It's pretty jarring considering 4e is ostensibly about making everyone Good-er, and the Unfortunate Implications of the mechanics makes it worse.

Tieflings are "evil" because they are descended from a bloodline that is eternally damned due to ancient pacts with evil demons. Individual Tieflings may or may not be evil, but the race is filled with ominous blood magic that Can't Be A Good Sign.

All Warlocks gain power by "cursing" people who then die. What is the connection with their Pact and this Curse that seems to trade their enemies' life force (soul?) for personal power. Don't even get me started on the Infernal Pact and its PP which literally eats souls.

Oh, and the Star Pact which is strongly hinted to be with Lovecraftian Powers.

Since the Assassin in 1e, I've not seen so much evil on the side of the PCs. It's even weirder than WotC doesn't even hint at this essential contradiction with their stated aims.

That isn't to say that I object to these features for being evil. It's just really, really weird... and I can't figure out whether WotC is playing a deeper game or just Getting Crap Past the Radar.