Well all I can say is, if you pretty much just focus on a couple of combat related skills then you probably will get too powerful, too fast. If you don't enjoy leveling up other, not directly combat related skills such as smithing, enchantment, then I can see having the problem you are having. Truth is, it does appear you aren't really a role player and just want the challenge, but this game is more about role playing. So, if you aren't really willing to have a more well rounded character that finds fun in creating powerful potions, or creating a power ring or armor, then I think you are just out of luck.
For me at least I see no fun in leveling, honestly. I could have fun as a level 15 or 81, fun comes from the story and variation in said stories.. something Skyrim doesn't have. Why would I want to do the civil war again? All I'm doing is clearing forts? Why would I want to do the DB again I'm doing the
EXACT same thing I did before. I may just see this as a problem because I'm a Vault Boy but really, being able to change the out-come of your story was the best game mechanic ever.