In our high school (at least in honors/AP classes) the typical breakdown is 70% tests/quizzes, 10% homework/classwork, and 20% final. In a number of classes, homework is a completion (vs. accuracy) grade.
I know that many gifted kids don't want to do boring or easy work, but my attitude with my gifties was usually, "tough luck, so sad, too bad," and I had the teacher send home anything they didn't complete in school (to be completed at home) because I think realizing that you're going to have to do a lot of things that you don't necessarily love is a good life skill.
That said, I did make exceptions for things like reading logs (which we, like many, just stopped handing in), or really useless homework (so they'd have to complete the map, but I would be fine if they got a lower grade because they didn't shade it neatly or carefully enough).
I think doing homework/classwork is often a bone of contention for gifties because it seems so easy and ridiculous, but I have two out of college and one in high school and study habits are actually necessary (if they go to a decent HS/college). In my son's honors chemistry class, they do lots of hands-on work, but the reading is done at home. Some of it isn't covered in class, so no matter how smart you are, you can't just "absorb" it or necessarily reason it out. In lots of the honors/AP English classes, reading was done at home and discussion/analysis in school.
Maybe I'm lucky, but my kids were never really turned off learning or reading because they were bored... or maybe I just didn't care that they were turned off for a while, because I knew that there would be other opportunities, more interesting classes, new challenges, as they got older, and I felt confident that the spark would always came back. Perhaps it was a bit of "fake it til you make it." Elementary school is actually the worst, but I think it gets better as they get older! All of my kids liked MS better than elementary, HS better than MS, and college even better. If it makes you feel better, the one who told me repeatedly in 4th-7th grades that she just didn't like school, nope, not really any part of it, yeah, she understood she had to do it, but she'd never enjoy it, and she didn't really see the point is now getting her third degree and wishing she could remain a student forever.
