An interesting thing about the Wrath of the Lich King Alpha -- well, one of them, anyway -- is the proposed 51-point Demonology talent for Warlocks. More than a few Warlocks have daydreamed about a Demon Form or being able to summon a Dreadlord for quite some time. If the Metamorphosis talent makes it all the way to release, both those wishes will actually come true. The interesting bit is this: two of the proposed abilities for the new form are melee-oriented. This means that Warlocks will actually need to adapt a different playing style when switching forms.
In fact, Warlocks might even have to start looking at a stat they've previously ignored -- top end weapon damage. In the past, weapon damage and DPS was irrelevant to casters, who generally only looked a +Spell damage (or, ahem, Unified Spell Damage). With a melee strike that deals weapon damage, as well as a Charge-like ability that deals normal (physical) damage, Warlocks move into uncharted territory. Will we begin to see Warlocks roll on weapons traditionally associated with melee classes? Or will we see a spike in top end damage for caster weapons? Does this mean that Warlocks will actually have to -- *gasp* -- raise their skill with Daggers or Swords? Of course, none of this matters if the abilities never make it live, but it's interesting to imagine Warlocks actually heading into the fray with the intention of poking their enemies with weapons rather than casting spells.