Magic is always going to be lacking, because Tamriel, in majority, still frowns upon magic, with the exception of some Elven provinces.
The game is set in Skyrim, the land where whacking something with a hammer or shooting something with an arrow will always be more abundant, compared to magic which uses the mind, something many of Skyrim's inhabitants dont use.
When using Magic, you must understand that you are taking a big sacrifice.
Its not down to the developers, its down to lore.
However, i do agree there should be casting on Horseback, and maybe the spell combination as seen in Game Jam.
Sorry, but this is all incorrect. It
is down to the developers, not the lore. Lore is just an excuse people are making for the lack of real spell variety, and it's a terrible crutch.
Many inhabitants of Skyrim don't use their mind? lol
Tamriel doesn't frown upon magic at all. I would say that magic is accepted almost
everywhere in Tamriel. Keep in mind Tamriel =/= Skyrim. There are only two reasons you get the feeling that magic is frowned upon in Skyrim. One is due to what happened at the College of Winterhold, the Great Collapse, etc. The other would be because the Nords in general have always been in conflict in some way with the mer. Whether it be the 500 companions and Ysgramor against the Snow Elves, or the Thalmor, or many other instances. That is why they don't trust magic.