I wish there was a hide red quests option... and hide quests not in current zone... Having to wade through all the extra quests to find one I can do... Sighso that means they're doing nothing but clogging up my quest log,
Make sure you alternate between doing sidequests, main quest and points of interest exploration.
Everyone is going to be completely bored and pissed if they clear all the smuggler's caches at sea in skellige (50+) in one go.
Mix it up a little bit and you should be fine.
Levelling is ok. It's balanced to put more focus on the main quest.
So...do the main quest. That is what the game is about.
Leveling slow?
No, it isn't. Unless you have the xp bug...
A thing you have to know when playing games, if you play too much like 10 hours every day, you are going to get burned, and soon you won't be in the mood to even play it, what i do is 3-4 hours absolute max and not everyday, it keeps it fresh and enjoyable.
Haven't felt bored at all. Maybe try to not binge play.
Just play something else for a while or do something completely different and return to TW3 when you crave for some more Witcher action again.
Personally I'm 85 hours into the game now and still fully enjoying it!