I'm wondering if Fullbringer Ichigo is going to continue the power curve of the series and be somehow stronger than he was before, or if this whole thing is an excuse to kinda reset Ichigo's power level because it was beyond the point of effective storytelling before.

If Fullbringer Ichigo is weaker than Vizard Ichigo then we have an excuse to have villains that aren't on Aizen's level again.