I don't think hes responsible, and I think that is the issue. The people he has handed off these shows too aren't very good, and clearly need supervision or to be replaced. Even disregarding badly written episodes (almost a given when you do 23 a year), the overall plot and story of The Flash this season, of Arrow this season, will anyone actually sit there and tell me that is good, that is what these shows should be doing.
Flash is so dam formulaic now, every season new big bad, they fight the big bad, big reveal about the big bag, different universes, relationship drama... everything resets.
And Arrow... team of jackasses, fights silly threat, flashback, team of jackasses, fights silly threat, flashback... relationship drama, moody sad sack time, relationship drama, flashback, team of jackasses, fights silly threat.