He seemed there enough to go with an "I'm back" taunt instead of anything else.
Well, the "cloud with spikes" manifestation is pretty different from the "always behind you" appearance HWWBehind has in Harry's GS memories of the fight.
But yeah, that might not reflect lesser power, maybe Walkers have a variety of possible forms, who knows how they work.
(A weird cloth ball thing flies out of HWWBefore when Harry 'kills' him in CD. Maybe that's the same as HWWBehind's cloud with spikes, and HWWBefore's "body" was a possessed corpse of a summoner.)
I was thinking that if he was fully powered he might want to do more damage rather than just kill his summoner.
But who knows, at this point in the series (pre-Winter Knight) the Outsiders might still have hopes of subverting Harry.