Two points
1) Scrambling - If you want to argue that Spencer wasn't innovative or didn't funk in this department then maybe you can make an argument. But, he was a fantastic scrambler. Great hip awareness and was phenomenal at keeping his head up.
2) Takedowns - Spencer, when not gassed, is a phenomenal takedown artist. He didn't need a go to takedown. He had an array of attacks to take his opponent down. He was also phenomenal at re-attacks.
Spencer was as complete as a wrestler as one can think of