The first six missions make up for it. Even then, I don't totally dislike any of the final four missions. The Library is dull but I can live with it. Keyes was a bitch on Legendary, but I didn't necessarily hate it.
Two Betrayals is great though despite being just Assault on the Control Room backwards. I get why many wouldn't like it though. Assault on the Control Room itself has repetitive indoor sections, but the outdoor sections are excellent enough that it's still considered one of the best levels in the entire series. Rocket Flood are also pretty damn awful.
I think The Maw is very good as well.
Ah, yes, the Negotiator:
General Kenobi
<sneaky beeping>