Bethesda breaks new boundaries and, of course, bug records.
So why would Bethesda stress over performance problems, scripting bugs, and other maladies, if they know the modding community will find solutions for them? Well, they wouldn't, and this has been the trend for the last three iterations of the franchise.
The game is indisputably a console port--one of the first major patches, for example, prioritized PS3 performance over other issues. The patch, also seemed to have the opposite effect on PC versions, populating Skyrim with backward-flying dragons. The menus and controls are optimized for a console control and the game lacks the UI customization PC users have come to expect.
Apart from the blatant PC neglect, Skyrim improved upon the franchise in many remarkable ways:
Combat
The fighting in the game was drastically improved. The battles felt more challenging and the character animations appeared more realistic/natural (though the rag doll effect was still abundant--but that's not necessarily a bad thing). Dual wielding was added to a player's combat techniques and dramatic attack animations added to the overall combat appeal. It was bloody satisfying. One that note, magic was shafted. Spells were restricted to the attack (mouse) buttons and very streamlined for console optimization--the 'c' cast button being sorely missed by many fans.
Jobs/Crafting
One of the best introductions to the game was harvesting mechanics. The additions and modifications made to crafting were amazing on their own, but with the addition of tanning, blacksmithing, mining, etc. the ordeal of crafting become so entwined with adventuring it felt like an extension of the story and leveling experience.
Perks Unbound
Bethesda took a lot of feedback from Oblivion and Fallout 3 to heart. Among other things, the Perks system was perfected. Instead of them acting as little augments to abilities, the Perks became more substantial, shaping a skill as a whole, pruning each tree to a hero's exact needs. This function lends itself to the sandbox mentality of the franchise by opening up character progression and really liberating player choice.
The franchise is certainly evolving for the better. It will capture new players for hours and there is unlimited potential for additional content and mods, whether created by the community or Bethesda.