Check out this review from 2404.org:
http://www.2404.org/reviews/4164/Sins-of-a-Solar-Empire-Review
Now, every reviewer has a right to their opinion, but if you are going to be reviewing games then you darn sure at least ought to get your facts straight...
The 3-way dynamic comes not from Starcraft, but from the fact that 2 races is just too few in a game like this, and four races is considerably more work than 3, especially when it comes to balancing. There is no need to ascribe the decision of any developer to use three races to some sort of Starcraft-based decision, it is virtually always due to a mix of game-design and economic factors.
Resource trading and diplomacy in games came about WAY before Age of Empires, and the mission system for diplomacy in this game is WAY different than the AoE system anyway. As for the resource trading, yes that is pretty generic, but the ability to leave stuff on the market for sale to other players is at least a little bit new and different.
Galciv II is SO not the father of the planet upgrading system. As a matter of fact Galciv's system is FAR closer to being a copyof the system used in Ascendency (1995) than the far more generic system used in Sins is copied from Gal Civ II's system. Indeed, in many ways Sins is far closer in design to Asendency than it is to probably any other game made to this point. (BTW, Ascendency 2 is in development. Hopefully it will be even better than the original).
The combat is not at all like Warcraft, I have no idea where is comment about that comes from. The LAST thing I thought of was Warcraft. It is actually closer to something like Warhammer 40k: Dawn of War, because this game is also focused on capturing and holding "resource" points. It is also about getting units through the battles with at least one member still alive so you can reinforce back to full strength for the next battle, much like Sins. Warcraft is about spamming crap as fast as possible, which you can do in Sins, but that is basically the only way to win in Warcraft, unlike Sins.
I understand if the guy didn't like it at the 90% level, or even the 80% level, but really 60% is way to harsh, and his whole line about the game coming from elsewhere is both wrong on many factual points, and pointless anyway. Most RTSs are 95% copied from other RTS's, and 5% original. At least Sins is 10% original, with the rest being 50% copied from RTSs and 40% copied from 4X games.