Popular =/= Good. See Injustice for example.
Johns helped turn Tim into mini Bruce, turned Kon into a generic angry teen with jeans and t-shit, turned Cassie from a smart, assertive tomboy into bland cheerleader archtype with a vanilla personality so he could push Kon/Cassie as a bland jock/cheerleader type couple and even Bart got a personality transplant during his run. He is also responsible for pushing the TT purely into Justice League Jr territory and acting like the team never faced any real danger before he took over even though they faced plenty during their YJ days.