They've explained how Kane always comes back every game, looking not very much aged, despite the huge timelime jumps between games. Not to mention that he normally dies at the end of every game.
I liked C&C3's cutscenes, I also liked the cast. The gameplay did indeed leave something to be desired, but I still liked it better than TS (TS is my least favorite RTS Command and Conquer game, Red Alert 2 is my favorite, followed by Red Alert 1).
What bugged me is that they so largely ignored TS's storyline. All the Tiberium monsters, the strange plant-like Tiberium groth that was forming. It was all simplified down to those little green crystals. Gone were the Tiberian Fiends and the vine monsters. And with no explaination. It was really odd.
I also agree that the jump back to tanks was poor. Why'd they ever use mechs in the first place if they were just going to decide "You know what? Tanks are better."
But my main issue with the game was how modernized it became. The sci-fi aspect was largely eliminated. There were no more cyborgs, guys using advanced weapons (Exploding discs, lasers, etc.) in war. Plus NOD, it became far more of an opposing millitary faction and more of a terrorist organization driven by religion. Kane seemed more like he wanted to be Jesus than he wanted just be a millitary leader and charismatic figure, in C&C3.
On the gameplay side of things, I thought the teams were too similiar. They all had the same bases, the same basic four defensive bases (Anti-Infantry, Anti-Armor, Anti-air, Anti-Everything but really Expensive). They only had a few subtle differences, but the plan for them all was the same. To spam the best unit and crush the enemy with it.
I'm not saying it was a bad game, but it wasn't nearly as good as I had hoped. I still liked the cutscenes and the cast, though, even if it didn't really follow TS...at all.