The "logical" reason is that I don't believe it would be very compatible with the dual casting system. I believe by creating customized spells, it would cause technical issues with the gameplay mechanics.
For instance, one exploit of the Spellmaking system that I despised, was the ability to fully level up one skill (let's say, Illusion), and mix your Master spell effects with the spell effects of another, untrained school, and be able to use high end spells of your untrained school.
Example:
If I am level 100 Illusion, I can cast a Master level On Target Frenzy spell. This means that the spell is now considered an Illusion spell, thus casting off of my Illusion skill.
Great, right?
But what it also means is that I can combine it with an Expert level Destruction spell. I am a Novice in Destruction.
But because the Illusion effect is greater, the spell works off of my Illusion skill, allowing me to cast powerful Destruction spells well above my level.
Now combine that with the current casting system, and dual casting perks, etc... and you have a mess on your hands.
There's also the fact that, specific spell effects have specific casting types. I.E.: Wards are a specialized, constant casting type. There are constant cast damage streams. Runes. "Hold to cast" spells like Detect Life. Instant casts like summons. Reanimations.
The Spellmaking would get all wonky, as certain spell types would be more customizable than others, leaving certain mages unable to access Spellmaking. For example, what would a Necromancer benefit from Spellmaking, when the reanimate spells are pretty specific in what they do?
You wouldn't be able to customize a bunch of different spells. How could you customize a Ward spell with a Rune cast? How could you combine a reanimate with Detect Life?
The previous system, because it was incredibly simple, made itself much more compatible to Spellmaking. This newer system is much more complex, so Spellmaking would have to walk a delicate tight rope to work properly. It wouldn't be fully customizable like versions past.
And if it's between evolved gameplay mechanics, or Spellmaking, well, I'll take the newer mechanics everytime out.
That's not to say Bethesda implemented the newer mechanics as well as they could. They left out tons of spell effects that should have been in. But out of the 2 choices, they made the right one.
I just don't see how Spellmaking would work with the current mechanics, without being incredibly toned down. Which people would be [censored]ing about that anyways.
Yes, there could be some cool things that could be done with Spellmaking, even with the current mechanics, and I am not against a Spellmaking feature in future DLC. But Spellmaking as we've known it would not work in Skyrim.
Personally I have been for bringing back Spell Creation this whole time...But, this is the first time I have read someonelay out a well thought out counter, and that should be recognized. Cheers.
That said I can see what your saying, and it makes a lot of sense. Yet, there is a lot of stuff missing that could have made UP for the magic system that was left out.
New casting options were added, there is a better focus on strategy for mages... it's an interesting deviation from the norm.
That said, we have still lost a LOT... that could have been made up for the loss of spell creation, yet wasn't included.
I really think that Magic mods will quickly overpopulate modding sites, because there is so many directions we could have been provided yet weren't. Before I continue on that though, I don't think Bethesda put anything to gather poorly. Everything they put into Skyrim was thought out and for the most part appreciated. And, often, the more is better (Which is integral to the arguement for Magic creation) isn't always true.
The issue here is that for a game that is so devoted to making an immersive working world... the removal of something like this, seems counter to their goals. It's not like, no one makes spells, you get spells from that Cat in the College of Winterhold, and he says: "Oh try out these spells I have made." Why can't he do it, but we can't?
Also, going back to the: Well there are new types of spells you can cast, liek Runes and whatnot... yes, that is true, but 64 is a pathetic number of spells, when spaced out over as many schools of magic as it is, and your only left with a couple of chocies at level of how you can do something. Destruction levels as follows: Flame-thrower, projectile flame ball, projectile explosive flame ball, flame cloak. Then there are alternatives for Frost and Lightning. This is rather standard, but thats it. For a SCHOOL OF MAGIC, that seems rather... limited. What about some sort of destruction magic that uses streams of air to slice stuff up? What about pure energy of some flavor that disintegrates? What about elemental combinations like a wall of air that shoves you back, intensifying inner heat to make you combust, draw out all the water from your body to dessicate you? All of these things could have varying strengths from: A mild annoyance, to life threatening. What about pure magical energy instead of just elemental?
There is variety, but there isn't choice. if there were many more options for spells or effects of spells, I for one would forget about Spell making, like I did Attribute points.
Here is something else, even if you didn't have mad variety: Why not have more combinations of magic? If I cast a flamethrower and palpatine fingers at the same time... Well then people are effected by ligthning and fire. Thats boring. What about if I cast a summoned boulder at someone, and use a fireball at the same time? Two seperate spells again, wow again boring.
now, what if I were to combine fire with boulder and throw a fireball weight of 75lbs at someone's chest? That is awesome.
yes, I know I am saying: "What if we added stuff from the game Magicka into Skyrim" but why the hell not? Why the heck didn't we at least take SOME directions from that game's system? if we're going to loose spell making and variety of effects, why can't we have combination effects or counters... or SOMETHING like that?
The point I'm trying to get to here, is that even with the new system... there is SO MUCH MORE they could have made out of it, but didn't. They could have made it freaking amazing, but instead it is... Good, but still a shadow of what it could be. I would rather magic creation copy and pasted with no alteration out of Oblivion (Which was inferior to most other systems IMO) than what they have now!