Level scale main quest content, keep everything else in the world locked. How hard is that? People explore because they want adventure and challenge, no reason to take that away.
how is keeping the rest locked providing a challenge? essentially you will run into 3 scenarios. impossibly difficult, challenging, and piss poor easy.
so with locked world 1/3 the time you will get a proper challenge, 1/3 the time you will die horribly with no hope, and 1/3 the time you will strolll thru the enemies yawning along the way.
so 1/3 the time you get to have fun.
im not inherently for or against level scaling, i see the pros and cons of both.
but the only way to have a leveled game with static enemise is to make leveling mean very little, so while the level 20 boss is hard as nails at level 1...you can beat him without ai exploits or glitches...and at level 20 hes merely a good fight.
that means 20 levels would make fairly small difference in power.
ior you can go the way i described closer to the top where 1/3 the time you get to have fun.
people say level scaling removes the incentive of leveling, and the point...that depends again on opinion, of what your opinoin on leveling means, and how they scale the enemies.
if your sole thought on leveling is getting more powerful, then skyrim already fails miserably for anyone who specializes in anything aside from combat skills. in truth leveling has had a far greater reason for existing then you becoming more powerful, its you being able to customize your char.
Just htink in a actual fantasy world still largely guided by general principles of reality...just because you get stronger doesnt mean a sword cant cut thru flesh and a arrow cant pierce it as well...(not talking about armor here, but flesh) so in this isntance it would make sense to largely (but not completly) scale the damage of these attacks dependant on the wielder, the weapon, where your gettin ghit (ah location based damage already we advance past skyrims limits it seems) etc.
unless your armor stops teh attack...its going to hurt relatively the same at level 1 and at level 50 in terms of how much % of your health should be damaged.
now say a enemy is good with a blade and gets a "lucky" or "skilled" hit in slipping it between the armor...more damage!
now what woudl realy stop tehse attacks, your skill and your equipment...daedric armor is gonna deflect/lessen these weapons damage on you, your skill (those things you gain while leveling) can allow you to better avoid the damage again.
so if you want to look at it from a more reality based perspective...scaling within reason makes sense...because a bandits a bandit..sure his iron sword may bounce off your daedric armor...but if it slips past....its gonna hurt just as much as if you were level 1.