Yea it's hard bc he's such a grump when I wake him from a nap.
Many people say this but also report that with a quiet time immediately after capping, staying in the room for LO to come around - or offering a drink or snack or reading a book etc that their LO recovers relatively quickly. I think on the whole those people who find something that works to reduce the post-capped-nap-grump do find the shorter nap helps get the night longer again.
Flip side, I mention my DS, his grump and bad mood was just awful, it continued the entire afternoon and he did not recover until 1hr before BT and by then the day was over and BT routine was starting. I just couldn't keep doing it, it was horrible.
I'd stick with your routine as much as you can for now. It does sound like teeth and developmental doesn't it? I would hope the worst of it will pass and you'll find yourself back to almost where you were. The problem with long naps really is the late BTs, 10pm is pretty shocking isn't it. I only had one or two nights like that which were the really bad teeth nights when I ended up bringing DS back downstairs due to the level of hysteria (and yes I put kids TV on! anything to distract him and stop that screaming!).
Sorry it's so hard x