Just curious to see what levels are being achieved by players by the time they beat the game or by the time you get to Act 3? (without cheating)
39, close to 40 and I have no more monster contracts or side quests. All map locations are opened up in Velen, White Orchard, Novigrad, but I still have sunken treasure in Skellige to grab. All poster boards in all lands completely cleansed, and Kaer Morhen quests are fulfilled. It took me longer to get from 35-39, then it took me to get to 35. Being rewarded 5XP for each quest is crap. I jumped for joy anytime I discovered an area where bandits took over settlements because those reward you a whopping 50XP. LOL.
They definitely didn't think about the leveling in this game. Considering you can attain an easy 34-35 from the story alone, considering you did some quests and monster contracts along the way, they sure as hell didn't put any post-story enemy or quests in the game. With the way this game works, you want to be fighting level 27-30 monsters at level 23-25...but once you are actually 30-35, you're completely SOL and the game just drones. You look at a bandit in Skellige and they die. I got to the point where, I put my swords away and fight certain enemy with my fists LOL. Clearing bandit camps out with your fists is hilarious.
If I did it all again, a third time, I would definitely do all the side quests and contracts first, then story last. That might get you further in level. Doing al lthe quests and contracts while you are within that level range, should yield you more XP and the story should always reward you a set, static amount. Depending on whether you performed all objectives. What I do is balance it out and do some side quests while going through the story. Especially, my first play through. I learned, from Skyrim and Oblivion, that if you do too many side quests or nothing but side quests, first, you actually forget what the story was about to begin with. That's what they now call Skyrim Amnesia, right?