Demon Souls is in no way inferior to its successors.
Of course, it lacks some quality of life changes and has some janky mechanics, but overall this entry is a milestone.
I played the original on PS3 back in the day and one thing the remake has really improved on is the storytelling.

The only negative thing is the difficulty... for a souls game the bosses are a joke. Somehow the last fight of an area is always the easiest, which takes away all the tension.