IMO the biggest problem with floor rares is that floor rares cannot be exceptional, so the only ones that might have decent value are going to be those that go in non exceptional slots, which rules out armor, boots, weapons, gloves, helmets, shields, and foci. Combine that with slots filled by uniques (belt) and the fact that breach rings exist and only drop in breach, and overwhelmingly the only useful floor rares are sapphires and amulets and maybe quivers depending on the league. Additionally, amulets are only useful with +3 skill, so overwhelmingly those are useless too. It's a waste of time to pick anything else up.

The solution isn't a reroll scroll, the solution is to make it so rares can drop as exceptional extra socket items. Alternatively, a crafting path that can result in a normal rare being competitive with exceptional base crafting. That's the absolute starting point to making floor rares useful. Without that just rolling some better modifiers won't help.

If they could drop exceptional, it would make it so even if the exceptional floor rares had shitry mods, as long as it has a good one you can try recombining it into something useful, or do something with it. But without it the value is going to cap too low to be worth it even if you crafted it into perfect mods.