Curious about this subject because I'm reading about how some players are power leveling certain things such as smithing and enchanting, and then complaining that the game is too simple.

Currently, I've rerolled once. I started as a high elf caster type, and now im an imperial single/shield hybrid mixing it up. I find I've leveled 3 times faster then my Mage, which makes sense. Every fight I'm skilling up single hand, block, heavy armor etc where as a Mage it was destruction magic and conjugation, which seems incredibly slow now.

Essentially my question is, because I refuse fast travel to keep the game as realistic as possible, being at level 21 and on the 3rd or 4th chain quest of the imperial faction, is my level proportional to where I am in the story line. I understand that the game difficulty adapts to your level which is a great concept, but I don't want to find myself to be close to capped out on the perks and skills of how I choose to play with hours and hours of gameplay left

If you don't use fast travel and you walk around a ton, you should put the difficulty at the lowest possible, otherwise you're going to end up gaining a lot of levels from swinging your weapon/casting spells/being hit

But playing in on anything aside master I find is boring. I want the threat of death from every fight or it loses it's intensity for me.

Ok well, on Master you're going to be hitting a single enemy loads of times which means loads of levels

Moreso if you're walking around on foot everywhere you go. So then yes you can expect to be very high level in a very short amount of time.

I suppose you're right, but in defence ( no pun intended ) an enemy can 2 or 3 shot me with full steel so I don't level heavy armor as fast, essentially I become a glass cannon on master mode?