I think that main problem is lack of support for the former. Some people really like to do that, but rolling your own is hard. There are some third party supplement that might fit.
GoldSeal
joined 2 years ago
I recommend using the 4th Ed lite version (free), and using the Caravan To Ein Arris (also free).
I took a page from Flee Mortals and use actions instead of spells for NPC combatants.
https://shop.mcdmproductions.com/collections/flee-mortals-the-mcdm-monster-book