The current concept has been proven not to work as intended: people min-max either to plate or cloth; there isn't any middle-ground. You equip your tank with plate, everything else wears cloth.
So, what could be possible solutions to this problem? Obviously, we don't want DnD 2nd edition chance to spell failure, because do-or-die dice rolls suck. DnD 3rd edition max dex modifiers didn't work well either, with leather armors getting the same armor scores as plate if you accumulated enough +dex and no incentive to go lighter when you haven't reach max dex yet. And we definitely don't want to limit armor choices based on class choices alone, as that's incredibly boring and basicly defeats the idea of hybrid builds or battle mages.
I think a good approach should not affect DPS or speed at all, but instead limit the flexibility of the class. So, my idea would be to limit spellcasters in their spell choices depending on the type of armor.
Spells are divided into "difficulty"-tiers. This is not to be confused with the spell levels.
Each spell gets a certain difficulty tier applied to them:
1) can be cast with all types of armor
2) can be cast with chainmail and below
3) can be cast with leather and below
4) can be cast with light armor and below
5) can only be cast in cloth armor
If you wear plate as a wizard, you can only cast a selection of defensive or utility spells; if you wear leather, you unlock a selection of offensive spells of difficulty level 3 aswell. If you wear cloth, you get full access to all spells (difficulty level 5).
The beauty about this approach is that it balances the armor choices and the spell repertoire in the same process and allows for a powerful tool for the developers to fine-tune the power of spellcaster hybrids. You can play your wizard or druid as a glass cannon with the full spell potential or you could play them more as battle mages, using weapons as DPS and otherwise are limited to enhancing spells and some CC.
This way, you can basicly select your armor choice based on the spells you want to use for your playstyle. Or you can select your spell choices based on the armor choice. So your favorite spells are all available on leather armor? Great! But damn, you definitely want that powerful highlevel-CC that only gets unlocked when using light armor..., so yeah, downgrade to light armor then. But wait, maybe I can make up for the lack of CC with that defensive spell on the same level that can be used with leather?
The beauty about this idea is, that it even brings a logical explanation as to why you can or can't cast that particular spell: as you are encumbered, you simply can not perform the moves that are required to shape the magic into the right form.
It also allows for new cool spells that play with this mechanic: for example, a once-per-day spell that unlocks the next difficulty-tier of spells for a limited duration.
Again, this is not to be confused with the spell levels themselves. There should be spells on every level that can be cast on plate difficulty, so that when you reach a new spell level, you definitely have *something* to use. You just don't have the full repertoire at your disposal.
This system can also easily be applied to all non-magic classes aswell: certain moves and abilities are just impossible to do in plate armor.
Edited by Zwiebelchen, 18 March 2015 - 01:09 AM.