A note that may not have come up in your video, but from Morrowind to Skyrim the Daedric princes have been getting weaker. I have just (Finally) started playing Skyrim, and based on conversations the player has with the princes, their power has been waning since the Oblivion crisis. Yes, Oblivion had lots of Daedric stuff, but that was the point. There were so many Daedra wandering about that people could get it. Yes, the bandits would make more money selling the armor and moving into town rather than trying to rob the Hero of the Empire, but then you wouldn't have any bandits past level 15, when the elven armors start showing up regularly. Anyway, the conversation with Clavicus Vile during the start of his quest sounds like that with the barrier between Oblivion and Nirn so reinforced by the sacrifice of Martin Septim and the outlawing of Daedric worship their power has waned, so their associated items are weaker. A good example is Azura's Star. Even in Oblivion, all you could do with it was what Azura said. However, in Skyrim, her power has weakened so much that not only can a mortal use it to try to become immortal, another mortal can corrupt it to hold black (human) souls. At least in that part, the items becoming cheaper and weaker makes sense.
As to your other points, yes, there have been some weakening of the games for casual play, but based on the sales of the Anthology, the popularity of converting Morrowind to Oblivion and now Skyrim's engines, and the return of the class systems for Elder Scrolls Online (And probably future games) these may have just been to pull in more players, introduce them to the world without dropping them in hardcore, and then letting them loose on things. It's like the Beginner's Box for Pathfinder. It's a simpler version of the rules system, but it still has the same bones as the regular Pathfinder. Like D&D over the years. 4E is easier than 3.0/3.5, which is easier than 2nd, which is easier than 1st. Now, that doesn't mean that it's better, but it can pull people in. And honestly, there were problems with all versions of D&D. I do hope that you are wrong that TES will get dumber, but we will see with what happens after TES:O.