Some people are ragging on Gunn for saying this, but the main problem the DCEU had was that it was trying to milk the success of the MCU without putting in the work or being its own thing. I think it's very smart not to embrace '97's success as a greenlight to begin reviving every old cartoon.
As much as I loved JLU, its time is done, and DC's animation division is the one thing they have actually done well with when it comes to mainstream media. There's no reason to look for gold when you already have it.