This is for the best. I think CW needs to thin the herd, anyway, with the Arrowverse shows. They have the quantity but lack the quality.
But they aren't thinning the herd.
Whilst it's not a replacement, Supergirl doesn't get renewed, but we're getting Superman instead. Arrow wraps, they try and launch that Canaries show (whatever is even happening with that at the moment anyway?)
We've also got the newer shows in Batwoman and Stargirl (the latter of which is well received, the former, not so much - but we'll see how that does with it's second season). The problem with a lot of these shows isn't the quality, but the quantity in the sense of episode numbers. Stargirl (in my opinion) was that much better because it was a shorter run. Generally shows that don't span half a year are better received because there's a stronger focus on the story and less drawn out concepts.
Black Lightning and Stargirl have stood out for me in that regard. Season 8 of Flash, Season 3 or Batwoman, and any other series that's launched under the DC banner should take note of that. 10-12 episode seasons is ample. If needs be they can always expand the runtime from 45 to 60 minutes.
How long do y'all think Flash got? I'm sensing season 8.
8 at a minimum, double digits (10) at a maximum. I don't see Flash continuing beyond Season 10. Grant's going to want to try other avenues at some point, and by a 10th season, they'll probably run out of decent stories anyway.
Of all the CW shows (at least the superhero shows) Flash, for me, is the one show that
could become a sort of Legacy show, so whilst the story of Barry Allen/Gustin Grant could be wrapped up within 8 or 10 seasons, there's nothing to stop the show from continuing on with a different/reformed Wally West, or even a Bart Allen.
Assuming they keep John around, we're two down already here, and I don't see Legends sticking around for much longer. The CW Justice League is truly doomed.
I honestly think Grant is better than the CW. Same with Melissa. They both have bright futures after their shows IMO.
As
@MCU King has stated, Melissa has more opportunities than Grant, so Grant may want to stick around for a little longer...