I picked up speed after hitting level 40! Infact im already well into 30 million exp. Thats 10 million xp since the begining of november with almost no lucky eggs and a few evolutions durring one event.
I dont raid very much. My new objective is gold gyms. There is a very active playerbase in my area but not so crazy that gyms cant last all day - or in some cases much longer.
You know im always on the hunt for shinies.
The last side project im enjoying is powering up perfect or near perfect IV candidates of some of my favorite or more obscure mons.
To summarize 40 hasnt killed this game for me or fore the vast majority of my fellow trainers