The most important thing for me would be a modular approach, at least in regards to the textures. I’d love to be able to change from a steel texture to a gold texture and so on. Some weapons sold in marketplaces have extremely specific UV mapping which makes it a pain in the butt to change materials. As for variety, I think you’re going for the right approach by making weapons – I’m not interested in specific weapons that have ornaments, skulls, and whatever. On the other hand, good quality is a must (to be specific: I love the quality of your example sword; every weapon in the package should be at least that good).
The list that provides looks extremely good and I would definitely buy a package containing the listed weapons.
Edit: I was taking this for granted but maybe it’s worth mentioning – these weapons should be UE4 ready in regards to material set up, size, etc.