Not sure what platform you’re on but I main Kleese and that’s the strategy I pull on the overgrowth map. For Echelon I just stay back and set up a line of energy rifts and watch the side lanes for anyone trying to sneak behind us. That tactic for overgrowth seems cheap ,I know, but it works and I’ve been killed plenty of times attempting it but also lead our team to victory by at least causing a distraction. Remembering Marquis can be near untouchable while cheesing the sentry from the ledge. To counter Kleese at this point, assign someone to keep an eye on that lane and destroy any energy rifts that pop up around the sentry, they deal damage over time. Kleese is a big target and doesn’t move too fast so if you are thorn or marquis you should have no bother chasing him down and finishing him off. This strategy is best against teams who aren’t well co-ordinated or are too focused on the front lines.
Oh right, XBONE, I’m on PS4. Seems universal then, it’s an annoying strategy but it can be countered.