I definitely second the suggestions that these diseases be more difficult to cure and have more dire consequences if you fail to do so - such as player death or incapacitation. It's just too easy to visit an alter, use a cure disease potion, or spell - and the vanilla diseases hardly affect the player - I think the worst one is Vapors, where your magicka doesn't regenerate.
I like the idea of having to use the potion, alter, spell every day until the disease is cured. Maybe once the disease progresses, you have to find more potent means of curing yourself, like making a special potion, or being more skilled with restoration (there could be different levels or qualities of cure disease spells and potions.). You could also pay NPCs (maybe priests?) to heal you.
This would make avoiding the disease in the first place and curing it as quickly as possible much more important.
I like the idea of paying a priest to cure you. It takes more effort to raise the money than to activate a free altar.
As for cure potion dose pacing, a timer should work, such as one that counts the number of hours/days that go by to take your next potion (24 hours sounds good). As a matter of fact, let's add some risk: drug overdose. This should be implemented similarly to the Shivering Isles quest which makes you poison the Duke of Mania with an overdose of his favorite hallucinogen. If you actually made your character ingest the ingredient (the drug), you immediately notice side effects represented as nighteye and some drain effects, all on very large timers. If your character takes two more doses within that span, he/she will
die. This is all due to a custom script applied to the ingredient, so what must be done to introduce a similar script in all stock potions, player-made potions, and mod-added potions would be to use a function in OBSE that would mark any potion carrying a
Cure Disease effect with a token that adds this scripted effect. This however should only work on players, since NPC disease work more like potions in script.
It would add a very nice touch to Cure Disease potion limitation, but the timer needs to be worked on. The normal spell timer works on the amount of real time seconds that go by, and the span of a day may vary depending on the timescale you use. An OBSE script check to remove the effect the moment 24 hours passes should work, however.
Altars to cure disease never made since to me.
Altars to cure curses does. Maybe some of the diseases could be seen as curses?
Maybe different diseases need different cures - or at the very least different altars?
But yeah Medicine men/healers and or exotic ingredients for curing yourself. Books on the diseases so that one could learn to themselves.
Actually, I noiced one of the next version diseases go by the alias "Caliron's Curse", and your suggestion is great! All the needs to be done is implement an additional tag to mark the pestilence as a "disease" or a "curse", and now there can finally be something done to infect ghosts and wraiths!
Also, good idea on different altars. Some diseases may only be dispelled by activating one of the other small altars in a chapel, or visiting a wayshrine. Different cures would require a scripted potion, but it is possible.
New NPCs can be a stretch, since adding them to a world via placement or spawn points can cause problems, and they won't have voice acting (unless someone looks through all the voice files to see a voice MP3 that works). Different ingredients can be another obstacle, since editing leveled lists for creatures and chests can be a problem--adding them to a merchant seems okay though. Books on diseases seems fair, like Bethesda's spellbook official plugin. But then a player's spell list will be flooded with various "Cure Disease" spells of all types, so please elaborate with more ideas for implementation.
A flaw in implementing these specifics however will be that adding custom disease records to the game will be a difficult chore since the disease records needs to be accompanied with additional spells, potions, scripts, and other, all which may not be present since the modder who made the mod to add new diseases was only attempting to modify default Oblivion, and didn't know Vector
existed.