I only thing Skyrim is better off without it because I don't believe that technically, Spellmaking (as people want it, anyways) could work with the gameplay system Skyrim has in place. And if Spellmaking did make it in, at least as I imagine it working, people would cry about how dumbed down it was.
And I've tried to elaborate, but I'll try to do so again:
1.) Dual casting. Someone earlier used the example of a Frenzy / Frost Damage custom spell, and that dual casting would simply increase those numbers. Okay, on the surface, that sounds good. But beneath the surface, what if someone has only taken the Illusion Dual Casting perk, but not the one for Destruction? Do they get the benefits of the Destruction Dual Casting perk without ever having taken it? If so, that's unbalanced (and I know that people claim Smithing and Enchanting to be unbalanced, but that's not an excuse to add even more unbalance into the game. And it's even more of an unfair unbalance, because at least the Smithing and Enchanting exploits and unbalance would require investment from the player - both in time to level the skills up, as well as perks to get the needed perks to "unbalance" those skills. Being able to unbalance a magic skill without even having to put investment into it ends up being reward without risk). Do you not allow dual casting of custom spells? Well then that negates the purpose of the Dual Casting perks.
Also, as I explained in my last post, the ability to cast high end effects from an untrained school, by combining it with a slightly more powerful effect from a trained school, is an effect of Spellmaking that I never liked.
2.) Spell casting types. We already have different types of casting types in Skyrim. There are constant casts: Wards, Detect Life, DOT stream spells, some healing spells; There are instant casts: Shield spells, Conjure / Reanimate , Frenzy; There are the proximity trigger casts like runes. How do you make those work in a Spellmaking system?
Do you allow differing cast types to be combined into one spell? I'm no programmer, but that sounds like a coding nightmare, asking for all sorts of technical issues. And people are already complaining about bugs. How do you combine a constant cast Heal spell with a proximity trigger rune spell? Or an instant cast Shield spell with a constant cast DOT stream spell? I feel like that's asking for all sorts of issues. Do you restrict the types of spells that can be combined together? Well then you start restricting what makes Spellmaking so special in the first place. I can already hear the cries of "dumbing down".
I acknowledge this is a lot of "theory-hammer", but that's just how I see it. I imagine even if Spellmaking didn't cause technical issues, it would still be clunky as all get out with the mixing of schools, cast types, and circumventing of perks. And for the argument that "well they shouldn't have used this system", I will say that I would much prefer to give up Spellmaking in favor of what I feel to be a far superior combat and casting system, than to give up this combat and casting system just to keep Spellmaking around.
Spellmaking was cool. It wasn't -that- cool.
As far as it being one of my favorite features but I feel better off without it, again, I only feel "better off" because I just don't see it fitting into what Skyrim is as a game. If Skyrim had kept the same Morrowind / Oblivion system, then I'd agree, keep Spellmaking. But I don't think it would work. And that's why I feel we're better off.
If Bethesda proves me wrong, and makes it work, and releases it in a DLC, then I'll be the first to line up to buy it and use it. But I just don't see it working.
What I'd prefer to see, instead of what I imagine to be a clunky Spellmaking system, is to instead amplify the current casting system even further, allowing you to actually "combine" your spells together - I.E. actually combine Frost and Fire spells together, or Frenzy and DOT spells together via the dual casting system.
Ok listen up. I won't go and invent a spell making system on my own since it will go to waste and there would be no point in it. I'll answer to your concerns though.
I believe you worry too much - your mind goes too far - while there can be only a few and simple limitations that would solve almost all of the problems you describe. Some of these limitations were already in the previous TES games spell making.
-Dual cast perks: Applicable only when you cast the same type of spells (as it is now approximately) - for example: 2 same effect "Bolt" type spells would only trigger impact (like it is now). Same with other schools such as illusion which - 2 same effect spells would raise the cap level and duration of the spell depending on their power (like it happens in Skyrim atm).
-About effects spell type - if you remember - there were some limitations on the previous games too. Not every effect and parameter would be applicable for any type of spell - or else it would be total chaos. For example heal would be only applicable to "Bolt", "On touch","Aura" type spells. Simple as that.
Now about certain types of spells:
Bolts - adjustable AOE, damage, velocity (in a certain extend), duration
On touch - adjustable AOE, damage, duration
Rune - adjustable AOE damage, duration if being active, duration of effect
Spray - adjustable angle, damage, range
Wall - adjustable AOE, damage, duration, duration of effect
Summon - adjustable object of summoning, duration
Self-cast spells - adjustable benefit magnitude, duration
I'm sure i forgot a lot of things and something i posted with 3 minutes thought is not flawless but these are just examples.
Now a very simple categorisation:
Fortify/heal spells
Damage spells
Pure effect spells
ETC ETC
Now setting limitations for example: Fortify,heal spells can't be set with the Wall,Summon,Rune types. They can be set with the spray, self-cast, on touch and bolt types.
And so on....
Certain limitations were already there in previous TES games and a very customisable - but not chaotic - system could work in Skyrim and add a lot to gameplay flexibility, rp and playstyles without hurting anyone.