By changing diseases into quick videogamey debuffs, Larian also made their cures obsolete. You don't need Lesser Restoration when you can just wait 60 boring seconds instead and save the spell slot. You don't ever need the Medicine skill which exists precisely for this. A skilled healer won't have a purpose, so why even play one?
Disease per definition should be a long term debuff to be interesting and meaningful. Diseases work well together with the concept of Long Rests and time passing. If only Long Rest would actually work as intended instead of just being a free ability reset button. An meaningful consequence from being diseased would be to replace the diseased party member with another while they recover, or to seek a healer.
+1
Specifically, many diseases progress (getting worse or getting better depending on a Con ST) after a long rest. This could actually work with Larian's free-long-rest-button, because long resting would risk your diseased characters getting worse. This would impose soft restrictions on soft resting, where players could be encouraged to continue adventuring to look for an item/npc that has higher level healing. Basically a mini-version of the Tadpole issue, except long resting actually affects its progression.
