I didn't say Spellmaking was tedious. I said that in it's place, we got an all new spell casting mechanic. Don't like it as much as Spellmaking? Completely valid opinion. But saying it was "removed for no reason other than to 'dumb down' to 'appeal to casuals'" is completely wrong. Spellmaking wasn't removed without a replacement. In many ways, dual casting replicates Spellmaking. Not 100% no, but it replicates many of the elements of Spellmaking.
Mysticism, and Hand to Hand in particular were not removed. Many of the Mysticism spell effects are still in the game. They are just in different schools such as Alteration (Telekinesis and Detect Life) or Conjuration (Soul Trap). Others, such as Absorb Magicka, are perks, or represented in the game through other spells. Ward spells, with a specific perk, are the exact replication of the Absorb Magicka effect.
Hand to Hand actually has perks for it (albeit in the wrong skill, I agree with that), and has entire segments of major questlines dedicated to it, where you have to proceed via Hand to Hand.
Athletics was removed in the form of a skill, but is represented through the Stamina skill that you increase or not, allowing you to spring farther. Not an exact replica of Athletics, no, but another method of accomplishing the same goal - getting to a destination on foot faster. Also, I didn't fast travel in Oblivion, but I felt the Athletics skill was a punishment, not a reward. It leveled beyond my control, and made my character faster than I wanted him to be, without any control on my end. I hate the Athletics skill, and tire of it constantly increasing for no other reason than I didn't fast travel.
Acrobatics was removed with no replacement, yes, and in my opinion, good riddance. Same deal as Athletics in my book.
Enchanting was removed from the game as a skill in Oblivion. If you claim that Pickpocket and Enchanting skills were "always" in Elder Scrolls, then Mysticism, Hand to Hand, Athletics, and the effects of Attributes that are now done differently, are still in Skyrim.
The fact that you say that "Smithing, dual casting, and sprinting" are the ONLY new things that Skyrim brings to the table proves exactly what I said, that people who play the "dumbed down" card only look at what was removed, not at what was added.
Things that weren't in Oblivion or Morrowind that are now in Skyrim:
-Smithing
-Enchanting (in Morrowind, removed as a skill in Oblivion)
-Pickpocket (didn't exist as a skill in Morrowind or Oblivion)
-chopping wood
-mining ore and materials for smithing
-Dual Wielding / Dual casting
-Marriage
-Home building
-Carriages (an equivalent existed in Morrowind, not in Oblivion)
-Cooking
-Various spell effects and methods of casting spells
^ That's just off the top of my head. Unfortunately I'm on break at work and don't have time to look even deeper at all the things Skyrim added.