The interchangeable parts on Cleveland are much better this year *because* they are designed to take advantage of GS' relative weakness (McGee/Pachulia v. Bogut/Ezeli). It's like CLE learned from GS the last two years, but kept a smarter, better James at the center of the mix.
Curry, KD, Clay, Dray, & Iguodala can outperform James, Irving, Love, Thompson, and Smith for periods, but will their margin at 42 minutes be enough to overcome their bench issues (Livingston, McGee, etc.) especially if James coordinates their style of 3-point attack while playing center with Frye, Korver, Shumpert, and Williams?
I think GS probably has enough consistency and mental toughness to do it, but they might surprise me, especially if they get arrogant like they did last year.