Hey, y'all! I was playing Skyrim as my 'Shadow Mage' and reached level 51 and I jus got insanely bored. I walked into Solitude and just killed everybody... everybody! Out of boredom! Is there anything I can do to make this better? I've completed every long storyline besides the companions and the bards guild... HELP!
Personally, I've never made it past level 40 before, usually start a new character around level 25-30, which seems to take about 150-200 hours each time (playing on Master) and doing one or two faction questlines.
The vanilla game world encounter zones are designed more for characters between level 1 - 50. It's not scaled unrealistically to the extent that Oblivion is, for example. Instead, there is a form of scaling like FO3, where there are higher level areas and lower level areas. Once you get up around level 30-40, a lot of the combat encounters become less challenging in lower level areas.
If you are on PC and want to experience more challenging combat above level 50, I'd recommend installing some mods that spice things up at higher levels, like Deadly Combat, ASIS, Deadly Dragons, Realistic Wildlife, Occupy Skyrim, etc.
Also, keep in mind there seems to be a leveling multiplier bug in the Civil War quest resulting in the CW enemies spawning at very low level, so if you are above level 10-15, the CW battles are probably too easy. You can fix this specific issue with the Unofficial Skyrim Patch.