New twitch can still do it, all he needs to do is a decent deal of lifesteal, crits, armor pen and damage items, go into stealth, wait teamfight to start, pop ultimate, pentakill. The difference now is that new twitch needs help to do it, old twitch could stop a whole push by sitting at turret and shooting his ultimate when the enemy team tried anything, I know because I played twitch and several times I've killed whole teams this way.
Anyway, gotta buy Taric before he gets rotated out, I'm curious about the new champion though.
EDIT: So me and Naxza just tried putting Kayle and Taric in the same lane, and it was pretty fun. We laned against mord and malzahar, and it was a pretty balanced fight, they were very aggressive but we just healed eachother backup and kept harassing. Regarding kills, we were at a stalemate. I would go in with exhaust and ignite and pick off a kill but mal's and mord's damage over time would get me, but then when this happened the other would have to play safe or risk being burned to death by Naxra and back off. Our lane only fell because 4 champions rushed us while our sion pushed and our ryze did... Something.
Our lane was the very last to fall, and eventualy we turned things around and won. Basicaly Kayle+Taric in a great combo, we would've completely dominated the lane if we weren't evenly matched with people that actualy knew what they were doing, and even then it took a 4 champion charge to get the best of us. We also contribute alot to teamfights and keep everyone healthy, we need to do this more often.