In general terms (since the concept of dumbing down isnt the same for everybody) I would say that to make more accesible something you make it easier to understand or do, so lets take players who started out with Oblivion as our little benchmark. I think picking Oblivion for this is perfect because it was the real mainstream breakthrough for TES, since it was the first to appear on both the 360 and PS3 consoles and the PC, and it was the first game to take a more action based combat system and use full speech for its characters.
BTW this is not meant to be a "Oblivion is better than Skyrim" thread; there are plenty of those and if not you are certainly free to make oone if you feel so inclined, and none of "the old school games are better Skyrim svcks" either
So...if you started with Oblivion and then bought Skyrim please answer a few questions, you can answer with a simple yes, no or give a more developed response
1) So your first TES game was Oblivion, did you like it enough to warrant buying Skyrim when it came out? did you buy it without checking reviews, or did you even buy it in presale?
2) Did you find Oblivion′s character development (mayor skills, minor skills, leveling system, multipliers) dificult to understand or overly complicated?
Is Skyrim′s character development easier (3 attributes, perks, reworked skills) do you prefer it to Oblivion′s?
3) Did the removal of some skills & atributes (unarmed, unarmored, spellmaking etc) and the reimagining of new skills (smithing, illusion, perks) change your playstyle, or altered it in any way? Did those changes make game easier, better, harder?
4) Did you think that Oblivion was difficult to understand and was overly complicated and because of that you didnt enjoy it and stoped playing it after awhile, and now you prefer Skyrim because it is easier to understand and more fun?
5) If someone didn′t enjoy Oblivion because it was difficult to understand and was overly complicated, would you recommend they try Skyrim anyway?