Well, sounds like it's new character time, maybe one with more roleplay emphasis?
With TES games, I find it takes me a few playthroughs before I can really make a character to "effectively" roleplay. The first few characters are just exploring, seeing what the guilds have to offer, and figuring out the main questlines, so I tend to rush through things. After I see how the game works, I can make an RP build that fits in the game world, and I'll tend to get more play out of it.
What usually gives me character fatigue is actually the running back and forth across the map. If I don't have a real plan for my character, I can get bored around level 20-25, because by then I've usually seen a good chunk of Skyrim and travelling doesn't feel *new* for that character anymore.
There are a couple ways to combat that. One is to develop a thorough quest plan. My current Nord is going through the Companions, then he'll tackle the main quest, and then (most likely) get involved in the civil war. There are a couple of miscellaneous quests that this guy will do as well - and the radiant quests will actually *help* keep me interested.
The other way is to avoid all major questlines, pick a section of the map, and use that as your base. Don't crisscross the province three times in a week. My last barbarian (another Nord) spent most of his time killing Forsworn in the Reach, just getting bounties from out of Markarth. That got him up to around level 15, and then he went off to see the rest of the world. Actually, come to think of it, he's sort of drifting now too...
Anyway, the best cure? Do something else! Come on, Skyrim can't satisfy your every entertainment need. I hate seeing those threads titled "Well, 6,783 hours in and I'm getting bored". Of course you are. Name one game you could play forever. Go play outside.
This is my strategy as well! I also try to vary the classes I play. My first character pretty much became the head of all the guilds and is now lvl 56. She's a dual wielding Nord warrior and followed the Stormcloaks.
Then the next one was pretty much the same, only that she's an Imperial. I have yet to finish that side of the civil war, but I just can't sympathize with the Imperials, so that toon is stuck at lvl 44 haha.
My 3rd character is the real fun one. Sneak, archery, smithing, enchanting, lockpicking, one handed skills are all at 100 and she's level 58. However, I just completed the Dark Brotherhood and Thieves Guild questline with her. She's still working on the MQ and she has completed a lot of side quests. But I just have fun sneaking around and killing stuff LOL She's the one that fully restored the TG to it's glory and she will also be the one to get every Daedric artifact oh and find the stupid jewels lol
Now, my current character went straight for the Thieves Guild and was level 40 when I started the MQ, because I missed shouting and slaying dragons lol
It helps if you have a plan and then work towards it. These games do become boring, if you don't RP your character. Use your imagination and imbue each character with their own personality.
