Let me guess... "Morrowind was better"?
Let me guess, i'm "just being nostalgic" for thinking that?
Trimming a few skills here and there is a healthy game design practice. If you were one of those guys that complained about Oblivion having Axes under the Blunt skill, you guys have issues and you might want to get that looked into. Because small things like this have very little impact on the game.
Maybe not, but removing skills such as Climbing, Athletics, Acrobatics, and Hand-to-Hand
does have a big impact on the game. Someone who never used them in previous games might not care - to them they're worthless - but then, I could say the same thing about magic.

I never play as a magical character, so perhaps Destruction is obsolete. Just use bows instead for ranged attacks.
Here's a healthy exercise: Look at all of the last three Elder Scrolls games and compare all the stuff they ADDED since Morrowind. I'm not talking about tweaked features or "fixes". If you can't name at least one thing without being sarcastic, then you're a lost cause.
There have been improvements, you're right. Just look at Morrowind's character creation with it's incredibly limited number of preset faces to choose from, compared to Skyrim's.
It's certainly not one big decline with every last aspect of the series getting worse and worse. Some things have been dumbed down, while other aspects have become more complex. The problem for me and many others though, is the aspects of the game that are constantly getting dumbed down are more important than the aspects they're improving. I think as a general observation it's fair to say that TES is getting worse and worse as an RPG series, but better as a sandbox action-adventure series.