I agree with some of what you said before, in that the supporters are not generally worse off except in terms of mainstream name recognition, but I don't think I follow your argument here. Yeah, the Flash line is floundering. But how is the logical solution to that sweeping Wally--whom most readers still identify as the main Flash--under the rug and starting fresh with Barry? It's a solution, since putting Johns and Van Sciver on anything will result in huge sales, but is it the best solution? I don't think so. It's a regression, plain and simple. Barry had his time, those stories are still out there for everyone to enjoy, and Wally is cusping on an almost unprecedented character evolution in comics--the journey from sidekick all the way to parenthood. I say "cusping" even though he's technically already there because, let's face it, it hasn't been handled all that well. With Waid, the kids overpowered everything else, and with Peyer, the kids feel like more of a minor subplot with the hyper-aging thing instead of a balanced, cohesive part of Wally's life.
This is going to be a supremely unpopular opinion, but you could say the same of Barry's "Well his stories are done" for Wally as well. Barry had thirty years as a headliner to Wally's twenty, yes, but in comparing the scope of stories and what they've done for the character, Wally far overshadows Barry. I don't mean that you should take a bullet to Wally's brain and just be done with it, I mean that when he left during IC, I was
ready for Bart to go ahead and take over permanently and for him to do something else with his time. No one's stories are ever really done, of course, just interrupted, but we're not even talking about Wally being
done, we're just talking about him not being in the spotlight. And, really, you never know. You say that Wally's kids overpowering everything was why they didn't come across so well, so who's to say that relegating the entire family to a supporting role isn't the way to fix that?
Are we even so certain that Wally isn't going to have his own book away from Barry, anyway? If they follow the method of GL: Rebirth to the tee, which included the main title alongside GL Corps, there's no reason for there not to be a Flash alongside a Flash Family or whatever. In fact, I'm going to go ahead and say that there almost certainly will be more than one Flash title after this.
At the end of the day, I'm simply not sure I see Barry as anything but yet another legacy in play. Not in terms of the actual story relations, obviously, but in terms of tone. Most of us have never even read a Barry Allen story before, and these new stories are obviously not going to be the same as those were.
Still, that's no cause to just bring Barry back and shuffle Wally off to someplace else--probably Titans, under Winick, which is basically a fate worse than death anyway. Why not just put Johns and Van Sciver on Wally's book? Why regress with a Barry mini-series and eventual, inevitable ongoing series when they could progress the Flash legacy overall? It's this regressive thought process that's endemic of many of DC's current problems, as far as I'm concerned. When in doubt, the current regime's response is to look backward and see how they can basically redo something that stands out in their minds. Barry's return, while I'm sure it'll be done well and sell like hotcakes, is another example of that. I miss the DC universe of just half a decade ago, where progress was the order of the day. Sure, they had a whole lot of misses, but at least they were trying instead of resorting to the safety net of the past at every turn.
I agree that I really do not want to see a Justice League with HAL! BARRY! OLLIE! and the old guard hogging up room and all of the progresses that DC has made shoved off to less public areas, but I can absolutely see DC's thought process here. As far as they can see, GL: Rebirth and what followed it has been one of their
biggest successes lately, not just financially but critically as well in the longterm. Seriously, what conceivable reason could there be for them to not try to mimic that? There is none. They could just have Johns and Van Sciver on a Wally book, sure, but there is absolutely no reason for them to not try this instead.