The routines always change bit by bit, but as they get older other things come into play as well including the balance of their "cup full" of emotional needs & stimulation.
I know it feels counterproductive that they get hyped up, but it's an important part of filling that emotional cup up. My DH works as the Finance Manager for the organisation in our State that provides help for parents with babies with sleep issues. They are just about to release a book and there is a whole chapter in it on the way the emotional needs impact their sleep.
I remember when my 2 were little & my eldest is a "do things with" kind of child, so you can cuddle him for an hour, but if you didn't spend time building lego with him he'd be harder at bedtime... my Ds2 is the ""physical closeness" child & if you played lego with him for an hour but didn't spend 20mins cuddling together bedtime would be harder. Both of them also neede that "crazy" time in the afternoon/evening & I found that if I stood them on my bed & pushed them back so they fell, they got the rough & tumble if DH wasn't home. The key was timing it so there was enough time to then calm down for bedtime.
It's also amazing how much toddlers pick up on the changes of a pregnant mother without really knowing why, so the fact you may not be picking him up anymore will have him wanting a little bit more from you to compensate & so his cup's not quite as ful at bedtime & so try that bit harder.
So yes cutting back on a nap could help, but at 2yo lots of it will be about the emotional stuff going on more so that the clock watching.