It is definitely possible to get multiple kills all at once or in quick succession with each other even after the patch. Of course, this is entirely dependent on the type of player using the roller and the type of player that you are facing. There are still many users who think the tactic of sticking together is the best option - which makes it much easier to get multiple kills. I've never been in the S ranks since I haven't been playing as long as others but I've seen videos... And being in the S/S+ ranks doesn't mean people always have the best ideas. ^.^"
It's also possible to get multiple kills or kills in quick succession depending on whether you use your roller offensively, defensively, or a combination of the two. Even after the patch, one could still get multiple kills if they play their roller right under the right circumstances. It's hard to say what those circumstances could ever be though since every match is ever changing with its players.