Morrowind, was truly an open game. Not having a starter dungeon made it all the more open. You never had to do anything in Morrowind, the world was completely and utterly open. Soon as you got off that boat, you were on your own. Only having vague directions to some place called Balmora and some guy named Caius Cosades, with little idea how to even get to Balmora. It took me awhile to even first get to Balmora. The world was wide open before you, an open world, with little idea what was going on, or what was even supposed to happen.
You could completely and utterly ignore the main quest with little consequence, it was not pushed on you whatsoever. You can easily sell your package for caius and get lost forever, there was no guide in morrowind.
The quests were fulfilling and fun. You had to have skills worthy of a position to be promoted to it.
Even with it's age, it is still the greatest.
Let's move onto Oblivion in 2006. The dungeons were bland, this is true enough. But the landscape was beautiful, and the game aged well. The quest were fulfilling. When you made Guild Leader, there was a real reward, and people recognized. It felt solid.
Now, Skyrim. The dungeons are great, shouts are cool, there are some new spells, and a new province, and it's generally fun.
Now we get to the cons which are the most numerous of all TES games I've played.
The game has become overly simplified, and to be frank, dumbed down to apply to the masses to make more money. The game was never really mainstream before Skyrim. Oblivion did well, but it wasn't halo mainstream.
You took Attributes, which is a killer. This hurts the game for me. Maybe I'm just being a bitter vet, but Attributes are a core of the game. This is an extreme dumbing down.
Next, perks. Perks are out of style of TES games, and yet they are introduced. They limit the usefulness of all skills and narrow your path quite a bit, no longer can you do everything as much as you want.
Birthsigns can be gotten from any stone at any time. No more one shot and that's it. At the same you time you limit people, you open more. Rather redundant.
When you complete a quest, it feels empty and not as rewarding.
When you become leader of a guild, it feels like nothing changed. Guards still talk to you like you're brand new.
Guilds are hollow now. There is no more series of earned promotions, you just go from apprentice to arch-mage, and that's it. They are all only a couple quests long.
Then you have the end battle with Alduin. How extremely anti-climatic and incredibly lame. Once again, nothing changes afterwords.
The only thing that really improved was dungeon design, and radiant quests are a plus, but they do not make up for lost content by a very, very, long shot.
Overall, Skyrim is fun, don't get me wrong. But there is a lot previous games did better. Maybe I'm just bitter, but take it as you will.