Certainly. The way to keep the challenge level consistent without making leveling just feel like a treadmill is to increase the complexity of encounters, not just the numbers. Oblivion did this very poorly: The only time enemies get more complex to fight is at the high levels when they get annoying spells like invisibility and spell reflection. Character progression needs to give the player new options and the new encounters need to provide exploitable opportunities for these options. And that's probably the most difficult problem to deal with in TES's Open World style: How do you really let the player go anywhere and do anything they want at any time while keeping the challenge level consistent AND keeping the game interesting by introducing new mechanics over time? Unfortunately Skyrim's not using this answer but here's how I would solve the problem: Perks are the right way to go here, but the perks need to be about the player's interaction with the environment. Probably the only decent example in Skyrim is the zoom perk for Archery: Suddenly, sniping from a distance becomes much more reasonable. All parts of the environment need to be designed to give exploitable situations with all perks (for example, all encounters need to have good sniping spots), but no individual perk should ever be necessary for completing anything, and the player should be equally versatile with any combination of perk choices (this is definitely the hardest part of the design). Provide progression in the form of enemies by designing them such that the basic tactics available from the beginning of the game no longer work and the player has to use the new perks they've chosen to use the exploitable environment designs. As the challenge level of enemies increases to match the player's level, give them more and more new powers that obsolete the player's old tactics forcing them to explore new possibilities.