To be honest, there's nothing wrong with the game. I think that it only suffers from the label "Supreme Commander."
On its own, it's a playable, and overall ok game, but it certainly doesn't do the large scale or strategy that the original and Forged Alliance did. My brother bought it and likes it over SupCom 1, but he didn't like having to constantly manage loads of things at once before you could start a proper attack, and I prefer the original, because it's, well, just more complicated, grander. As mentioned before, it felt like you were commanding an army, not a few squads. I also prefer the graphical look of the original.
So yeah, if you liked the original for its huge-ness, then this may leave you feeling a bit disapointed, but it still manages to capture some of the feel of the original's units (the Soul Ripper's still there ) and stands up to most of the mainstream (think of the latest C&C games (actually it's better than C&C 4. More like C&C 3 or Red Alert 3.)) RTS games out there. It's just not that different from the crowd, that's all...
PS: The one thing that genuinely pisses me off about SupCom 2 is the Aeon faction. Half of their unit names are puns! I mean, the Fighter/Bomber is called the "Weedooboth." We. Do. Both. What was Chris Taylor thinking...