The thing is we already have a perfect setup for it in destiny 2. How you may ask? Ana Bray and Bray tech corporation that's how! Ana bray is always asking us to let her know if we find more golden age tech out there. Siva is a golden age tech developed long ago by braytech. The same people that created the warminds. So why cant we get a quest or two one day to speak with Ana and rediscover a lost Siva foundry. Maybe Rasputin himself might actually help us out considering he used siva on the iron lords back in day. Maybe he feels guilty and wants to make it up to us lol. (Joking) Would be cool if we completed this quest then we get to forge Siva weapons and armor. Maybe even throw in a few more siva exotics.
Destiny has a wide range of lore topics we can explore further. SIVA was a big part of Rise of Iron back in D1. I'll let the team know you would like to see it featured again in the future. Thanks!