Writing gets more time consuming as you get better at it

Just finished the first pass through my novel. All through it I didn't really feel like I was doing much, but when it was done, I looked back and saw that I'd cut 11,000 words, so that's not nothing. But on a broader level, I changed nothing.

However as I was going through I was struck both by pacing issues and by issues with the primary antagonist. I believe in him. A person like this exists. But he didn't seem fully formed to me. And then just now, right as I was finishing, I was like, oh yeah, why is he doing all this stuff? Why is he so angry?

And now it's all like ugh, I have to: a) figure out what's up with him; and b) go back and revise every scene in which he appears (and probably add some new ones too).

It's a huge pain. Already I've been working on this book for two months, which, okay, isn't a really long time, but I've certainly put more hours into it than I put into Enter Title Here.