I've noticed my bar for "fast" has gone down quite a bit since the o1 days. It used to be one of the main things I evaluated new models for, but I've almost completely swapped to caring more about correctness over speed.
I think the more trustworthy reviews of products through sentiment is what I will miss the most. I really never read reviews anywhere else. I was even excited about https://www.looria.com/reddit doing review aggregation.