Barbas quest is pretty funny.
I'm still crushing every enemy. Upping the difficulty.
I've found that the default difficulty keeps up and (at least as a pure mage) forces you to get more inventive with your attack plan rather than just running in shooting fireballs, but I would tend to agree that it's not particularly challenging. That said, I don't want my first playthrough to be a grind/endurance test. I'm just going to enjoy being a badass for now and I'll try the next notch up on my next playthrough.
Morrowind was a kick ass game. That was my first Elder Scrolls game. I got the game of the year edition on the original XBOX. I put some hours into that game. BTW, Morrowind was an extremely hard to beat. Much harder than Oblivion or Skyrim.
Ditto for first TES game, though I played it on PC (got a free copy with a video card). I both agree and disagree in that Morrowind was extremely difficult early on, but as you got higher leveled and gained access to enchantments and powerful magic, it became laughably easy. I have clear memories of enchanting a ring that shot giant exploding fireballs and pretty much one or two-shot just about anything.
Oblivion was the worst of the three in that things never really got difficult, but they did get extremely tedious. Enemies weren't hard, but they would just level to the point of taking forever to kill.
So far, Skyrim definitely strikes the best balance. There are "zones" of different difficulty, and also some moderate scaling of enemy difficult along with the player. That combined with the overall more advanced combat, stealth, and magic systems makes for an experience that scales pretty well without becoming a total joke or a clickspam snoozefest.
At least that's my take at level 30 with 75 hours played