I've brought this up in other threads. I agree that Green Arrow is in that position where his cast is big enough to have more than one title, but he doesn't have enough sustainability to keep more than one title. And even then, his solo title doesn't usually sell that well. The only chance Green Arrow had for more than one title was during the peak years of the Arrow TV show, and even then that didn't help boost sales for the GA solo comic. I'm sure Green Arrow is just taking a break, for now, to make the desire for a solo book much greater than would've been if they just continued. That still doesn't solve Green Arrow's large cast problem.
Ultimately I suggested that the Arrow cast either gets a max-limited series (because DC has been loving doing those) starring one of the more popular Arrow side characters like Black Canary or Roy Harper. Personally, I would love a limited series with Roy and Lian (and maybe Cheshire). Another idea I had is team Arrow highjack an underutilized superhero team name, incorporate one or two A-Listers on the rosters to help sell the title (Batman & Team Arrow?), and a spin-off from there.
I know this is an off-tangent of Aging in the DC Universe, but all this talk about Green Arrow is drawn by the fact that Lian is now a teenager, which is about the ages of the DC Universe.