Not entirely. The didact opens some interesting possibilities with Forerunners, Anceint Humanity, and the Precursors.
The Didact opened*
I wouldn't call "interesting" the Crawlers and the Watchers. Because that's all they used him for. Oh yeah also Knights. Wow, the game was really lacking of those enemies.
Cybernetic, annoying, useless-anti-flood dogs? Great. I mean, Forerunners couldn't just purify planets/ships with laser (sentinels' type) beams. They had to send DOGS with pistols. Sentinels? Those flying, multi-purpose, shielded long-range devices? No way. Dogs, dude.