You will get many answers to this question. In my world, the jump from E to SE was very noticeable. 45K is a lot to make up, though. But if it is easy to do you may find it is worth it.

The 30% thing is gone now, but capacity control on flights outside of canada is a bit of a pain. The access to reward seats is easy to get used to. So is the Concierge. I use them all the time. 100% points bonus is great too.

If I dropped to E I would feel it right away.