And now... a real answer!
On one hand we have food recipes which are another kind of potion making.
Being part of the "over 30" crowd you reference, I remember Ultima 7. In Ultima 7 you could bake bread. Ultima fans thought this was just the most awesome thing ever, and were very disappointed you couldn't bake bread in Ultima 8.
That aside, this increases the number of objects in the game with which you can have a meaningful interaction. When you see a wheat field, you can harvest the wheat. That was present in Morrowind. In morrowind, you could then make a healing potion out of it (or just gnaw on it to restore an HP or two)... but Oblivion takes the immersion one step further by allowing the player to do with wheat what could be done with it in the real world: bake bread. (Note: having not played with the food making system, I don't know if you can actually do this... but I think the logic still holds for cooking and eating what you kill.)
On one hand we have shouts which are another kind of magic.
Well, Shouting has been a part of the Lore with regard to Skyrim since Morrowind at least... and quite possibly earlier (not sure if it was mentioned in any Daggerfall books). If they were going to make a game set in Skyrim, they pretty much had to include shouting. They do play fast and loose with the lore... but this was an opportunity that simply could not be passed up.
On one hand we have stones which are another kind of enchanting.
I'm pretty sure magical standing stones is also part of the "viking homeland" atmosphere they were going for. Unless, of course, you're talking about something else.
And I skip the game balance complaint, which I regard as categorically invalid in a series known for it's game-breaking exploits. All computer games have "god mode"; TES just lets you do it within the game's existing systems. Because it is single player, this is okay.
On the other hand we have far less spells
In-lore, the impression they're giving me is that standard magical practice (which the lore establishes as having originated with the high elf Psijics) is much less developed in Skyrim (where there is a prejudice against spellcasting). Out of lore, I would imagine they wanted to make sure there were things you could do with Shouts that could not be done with magic. Either way, the only effects that are missing that I personally miss (YMMV) are the transportation effects... but gamesas has, from the beginning, been gradually culling transportation effects in an effort to make level design meaningful. (I do not agree with this decision; it's the same thing as balance-breaking potion loops or what have you, which I'm also okay with.) Daggerfall lacked Passwall, which was in Arena. Morrowind lacked a climbing skill. Oblivion lacked levitation and teleportation. Skyrim maintains this decision. So it's not like this is some kind of new sellout tactic for Skyrim.
On the other hand we have far less potion effects
On the other hand we have far less enchantments
On the other hand we have far less weapons / apparel types
Not being a heavy magic player, I don't really know what's missing from enchantments and potion effects (though obviously stat raising is out). Having not gotten that far in the game, I don't know how many fewer weapon types there are. I remember iron, steel, silver, elvish, dwarvish, orcish, ebony, glass, and daedric in Morrowind. Oh, and Nordic. And the Akaviri weapons. I'm pretty sure the regular steel weapons are "nordic" in this game... but they also have "ancient nordic". They also have imperial. I haven't seen glass yet... but that was supposed to be a morrowind-only thing anyway (shouldn't have been in Oblivion, IMO). I haven't seen ebony or daedric yet... but that's just because I haven't gotten to that point. So I assume you are referring to weapon categories... but other than crossbows and spears (which were Morrowind, not Oblivion), I'm not noticing anything missing. As to armor, yes we have fewer pieces. I can see how this might upset some people... but I imagine it reduces their workload so they can focus on other areas (and Skyrim does indeed shine in places where Oblivion was utter crap). I'm not personally impacted by this decision.
Plus all t
he other design choices like number of quests vs quest quality / length or very limited effect of one's quest decisions on the game world or many other things. Even the UI is simplifying.
UI: simplified UI is a GOOD thing, so long as it doesn't also result in reduced functionality, and I detect no reduction of functionality between Oblivion and Skyrim... or even Morrowind, for that matter. The UI SHOULD virtually disappear in the player's mind, leaving him free to experience the game.
Limited quest effects: Again, no reduction from Oblivion (though, having not completed the main quest, I don't know of Skyrim lacks some equivalent to new statues and such). To find a better state there, you have to go back to Morrowind.
Which brings me to your question regarding the reduced depth of questlines, but the greater number of quests overall. Having played around with it, I think I prefer Skyrim to Oblivion in this regard. I find the immersion effect to be greater. Oblivion had some very nice, cinematic, linear quest lines for each of the major guilds... and there was NO interaction between them whatsoever. That was immersion-breaking for me. Skyrim doesn't attempt the same kind of epic feel for the factions, and as a result, my brain doesn't say "WHERE ARE THE INTERACTIONS!!!". It's just that each "guild" isn't saving the world in one completely separate way or another; the guilds are more day-to-day, so it feels more "immersive". I don't feel like I'm playing five completely different games on a coincidentally similar map.
Now, admittedly, I would have preferred they did what they did in Morrowind: nine fully developed factions, all intertwined in alliances and rivalries, with their questlines diverging depending on how the player wanted to influence guild policy with regard to other guilds... the stellar example being the Fighters/Thieves/Camonna Tong story. But to actually free up the resources to do something like that, they'd have probably have had to ditch voice acting. I would't mind that, but I am well aware that probably 75% of their customer base would consider that a deal breaker... so I hold my peace. Additionally, the voice acting does not svck as much as it did in Oblivion.
Now, these are just my speculations; I have no special contact with the developers. However, whatever their reasons, I do believe they have produced a better product than Oblivion. As to Morrowind... well, a man can dream, but nostalgia can only take one so far.