Interesting. Not sure if qBittorrent supports that, I really hate switching clients :D Swarm merging for V2 should be implicit because each file has a unique hash code. So you can't not merge.

Another thing torrent clients could do: Every torrent that is downloaded and "rechecked" automatically generates and "upgrades" a V1 torrent into a V1/V2 hybrid torrent for sharing. And when you add a normal magnet link you could get the hybrid v1/v2 torrent from others via DHT. So theoretically only one person needs to generate this upgraded torrent and it's not up to the uploader / tracker.