I recently (before Xmas) started a new journey and I immediately got sick of being diseased all the time from low level critters such as rats, bats and suckers. (pun intended)
Very early you don't have access to the spell Cure Disease - you have to travel all the way to Free Haven to get that. Got Cure Poison from Castle Ironfist, when I went there to get my bows and bow skills, but only the cobras and one of the head hunters can poison you, so it's much easier to experience diseases in the beginning.
I'm trying to refrain from 'cheating' as I've played this game many times and know most if not all of the shortcuts, but also know that they take away part of what the game was intended to be like.
Therefore I don't travel all the way to Free Haven before taking on the first dungeons - the spell Cure Disease is no lightweight spell either - 15 SP is a lot from a healer, only Cure Insanity is more expensive.
White and especially black potions is not something you should be familiar with in early game either - they are in my book cheats if excessively used before midgame - so that rules out Restoration too.
I guess my point is Disease is comparable to monsters with Kill and Eradicate, seen in the light of the toolbox you have/should have when you first encounter enemies with such specials. My knight goes from being the greatest asset in my team to being almost worthless when getting diseased. That temple can be a very long travel away if you're deep inside the Abandoned Temple or the Goblinwatch and plan on getting back again.