RTS Evolution at its best!
With that said Blizzard re-changes the definition of RTS that they had previously defined!
The game is just so flexible, like said before easy to understand and play notoriously hard to master just like all other Blizzard games. It didnt get the Best game of the year award for nothing!
Starcraft was always about macromanagment yet this game payed more attention to the micro aspect of RTS. While also introducing 2 new races UNDEAD and NIGHTELVES. I would say that W3:ROC has tremendous balance issues, but that is only natural with a game of such immense power and attention to gameplay. Anything can be done if you put your mind to it. But these imbalance issues have been resolved with the release of Frozen Throne and continous balance patches so that isnt an issue anymore.
ROC+Frozen Throne make Warcraft 3 in overall a formidable force in the RTS genre if not the best.