This is something I don't get. Why does less numbers automaticly mean simplified or dumbed down? Skyrim is streamlined comparred to earlier games sure, and the main reason for that is to reach a wider marked, but that doesn't mean it is less complex than Morrowind or Oblivion(but less complex than Daggerfall, which even though I find unplayable due to the control scheme I think is close to the ideal amount of complexity, at least when it comes to character development). Lets see at the facts:
Morrowind style attributes and classes(used in both MW and OB):
This simple(yes, simple) system where you get an amount of bonus points depending on how many times you level a skill is a very good idea on the paper, but since you only level by your major skills the game leads you towards maxing all of your stats regardless of archetype, while it isn't only making it possible, but easy. The fact that all skills are governed by their skill-level(with the exception of melee and archery which take about 20% from attributes, and speech and barter) also makes it pointless to try to specialize since a warrior/mage character isn't any weaker in any of the warrior fields than a pure warrior. A master thief/mage/warrior is equally good in any of the aspects are any of the pure classes, which removed a lot of the complexity with character development since it doesn't really matter in the end. OB is identical, but have mastery perks at cerain skill levels.
Daggerfal style:
At character creation you deicde how you want your attributes, skills and traits to be. You can have a very low attribute to get more points in another etc, and th skills are divided into three types of class skills and a non-class section. The Major skills will start fairly high(40-50), the minor moderate(25-40) and the last class skills low(20-25) with the non-class skills at "useless"(5-20) more or less, which by itself is very similar to the MW style. However you also have traits you can mix around with when you create your class, which can include, but isn't limited to: weapon specialization, resistance(all types), weaknesses, phobias(weaker against enemy X), hatred(stronger against enemy Y), health regeneration, magica multiplier, potential damage from things such as holy places and much more which all is optional combined with a slider that was automaticly adjusted by your traits which prevented you to get all of the good stuff and none of the bad, and the more "powerful"(closer to being too powerful to be allowed your traits) the slower skills increased. Combine this with the fact that you got a few points per level(4-6 randomly generated) which you could spend as you pleased in the attributes regardless of skill increase and you get the most complex character system on any ES game. Why? Because your character will be unique beause of your limited traits and attribute points.
Skyrim style:
No classes or attributes, but the character is defined as you go. The problem here is that most people read the first part and think "dumbed down" automaticly. I beg to differ: The skill value alone is only a formal factor, while the real power of the skill is located in the perks. Example: A heavily armored mage in Skyrim without any perks will get a very limited AR even with Daedric armor and move slowly which is likely to get him/her killed even if their heavy armor skill is at 100, but a character with the perks will have a very high benefit from using armor at the price of putting many of their limited amount of perk possible to gain. The same goes for any skills(maybe except destruction since it is poorly balanced).
The Health/Magica/Stamina choice upon leveling up also favor specialized characters over "Jack-of-all-Trades" characters forcing you to prioritize which are more important for your character. Combine these and you egt a character development that is more complex than MW and OB, even with less numbers to look at. Why? Because all decisions are pemanent and you cannot make a "Master-of-all-Trades". Two level 50 warriors in Skyrim are likely to have more differences than two level 50 warriors in MW.
Ideal Style:
As I see it the best solution for character development would be to cross Daggerfall, Skyrim and OB, having some major dections at the start of the game similar to the traits like in DF and having the limited attribute increase(AKA make it impossible to max them all out, and give them more meaning like a mastery perk at a certain attribute number(similar to OBs mastery perks)) and have perktrees in the skills so two characters who use Two-handed play differently.
Armor/clothing slots:
Less equipment slots makes for less quantity, which is bad, but it doesn't really remove complexity.
Spellcrafting:
A good thing to have, but is easily compensated by good variation and spellpower range(which sadly isn't as good as it should be in Skyrim).
The World:
More handcrafted dungeons with the addition of puzles and more unigue, less leveled loot. It's goinf back towards MW style.
Levelscaling:
MW was horrible. It was levelscaled(as in the enemies are chosen from levellists), but it was only scaled up to level 20 or so, so it becomes really easy past those levels.
OB overdid it,simple as that. It made the endgame fighting less boring than MW, but way to tedius.
Skyrim is starting to get close to a perfect system. Critter enemies are still very weak, regulars are weak, but not as weak and the strong opponents can be challenging if acconpanied. Bosses are pretty powerful and some have aditional powers(like stronger draugr can shout) and are more likely(but not bound to) have decent equipment.
Conclution: Skyrim is the second most complex Elder Scrolls game, it has just hidden its numbers, and that the negative progression started with Morrowind.