I think they had some of the Arrow show writers do a brief stint after Lemire, but it didn't really work and they only lasted a volume or two. I've always been sort of curious about Percy's New 52 run, because I love his Rebirth run but I hear it's mostly crappy.
But yeah, Lemire's run is top notch, easily one of the best eras for Green Arrow. I'd say it's second only to Grell, honestly... and maybe O'Neil.
Percy's DCYou run on Green Arrow was not great, but apparently a lot of that came from editorial. He's said in the past there were a lot of restrictions on what he could actually do with the character and a lot of his ideas were rejected. Rebirth was so good because all of those restrictions were gone and he could bring Dinah in and have Ollie in costume and things like that.