I hate to admit it, but I was wrong about level scaling. I always argumented against it but this game has such a poor balance and low difficulty that I was forced to try it out and changed my mind.
I tried
http://www.nexusmods.com/witcher3/mods/442/? out and it heavily enhanced my experience with the game.
a) It makes more sense. Geralt is a 100 years old monsterhunter. He doesn't get stronger during a the few weeks/months the game takes place.He shouldn't have problems to kill a single bandit or drowner.
b) It gives me the freedom to do whatever I want. Without level scaling, I had to do a lot of quests in Velen, then move to Novigrad and after that to Skellige. Now I can mix it . A few quests in war-ravaged Velen, followed by the calming atmosphere of the Novigrad outskirts. Furthermore it helps with the exploration and immersion. I don't have to flee anymore just because there is a skull monster in a "low level area"
b) The most important aspect is the challenge, I tried all the main variations of the mod and the one with enemies scaling to your level, while strong enemies being 6 levels above you is fantastic. A group of wolves or drowners can be dangerous if you don't watch out, but they are usually manageable.
The moment I decided to overcome my prejudices against level scaling was the quest "wandeing in the dark". I remembered the golem fight on my first playthrough.How challenging it was, how long it took me to defeat the golem. Yesterday on my 3rd playthrough, NG+ on Deatch March, the golem died in 15 seconds. The difficulty and balance in this game is frustrating. It's completely impossible to be challenged in the game without crippling yourself. Why are there even 4 difficulties if they range from no challenge to easy? (yeah I know it's subjective, but considering nexus is full of mods that make the game more difficult I'm not the only one who has that problem) Nevermind, with the mod installed I fought Nithral. It was fantastic. I defeated him first try, but I had to use all of my 10 potions, my 4 bombs and had 5% hp at the end of the fight. That's the challenge I want and expect from the highest difficulty.
I can highly recommend the level scaling mod. Common enemies like groups wolves and drowners will always scale to your level, whicb makes them manageable but still dangerous if you do are not cautious. Strong monsters and bosses (golems, leshens, grave hags etc) are always 6 (skull) levels above you, which makes them extremely challenging. You have to use all of your stuff like bombs, potions, decoctions, signs etc to defeat them. Exactly how it should be imo.
I can also recommend this mod:
http://www.nexusmods.com/witcher3/mods/424/?
It allows you to activate more than nine skills or activate a skill without using a skill slot.
With this two mods you get a much better experience. Geralt is a fully trained witcher and not a novice, so he should be able to parry arrows, but you wouldn't "waste" one of the 12 skills slots for it. This mod allows do "equip" the basic skills Geralt should know anyway without having to use one of the limited slots.
Still, you won't be OP. The game stays cahllenging in combination with the level scaling mod.