I don’t quite get this design decision. The class (and arguably its core identity, wrt flavor) revolves around the themes of cold and vitality. I find it a bit convoluted that its dedicated set is built on acid dmg and converting cold/vit to acid.
The logical progression of a reaper is to build it as a mainly cold dmg dealer and then when you get your endgame set you just completely reroll your character, find new boots/belt etc and redo your devotions for poi/acid. It’s counter intuitive, imho. Plus it becomes a bit redundant with witchhunters.
I can guess that this will be made optional as more items are added, but if it were me I’d start with a cold/vit item set and then add the acid set down the road to give the players another option.