It doesn't matter how the matchup in OU is going to be in Gen 7 or when Z comes out. Not is it all speculation and guess work at that point but our OU metgamae is ORAS at the moment and not Gen VII or Z. Because of that I can't agree with the argument you present and I believe bringing up how Aegislash helps making OU less match up based right now can be a valid argument for pro Aegislash peeps. You can't really disregard this argument with speculation about future gens.Since I've been seeing a lot of posts right now about matchup problems in the metagame, I feel I have to reiterate what I and a few others have said before in the thread. Matchup is simply never going to get better, and bringing something like aegislash down is like putting a band-aid on a gunshot wound. It'll help for a bit, but you'll still eventually bleed out. The matchup won't get better, because when pokemon Z or gen 7 comes out, we are going to get a whole lot of borderline overpowered megas that we will have to prepare for, and in gen 7, a bunch more non-mega threats to consider, plus new moves/abilities/items/buffs/nerfs etc. Gen 6 was the tipping point, and now everyone will have to accept that in the future, OU will be very matchup based. There will be threats like Lando-i and zard y that are impossible to switch into, and they will make it so if you don't prepare for one, you lose. If you don't like matchup, we can't keep bringing down overcentralized threats, because for one, that sets a bad example by saying, "this thing is broken and unmanageable, but we need to unban it so a bunch of other things aren't broken and unmanageable." The idea behind smogon's bans is to ban something if it is broken or overcentralizing, not bringing something back to limit it. Secondly, it won't work. Yes, aegislash may be a band-aid right now, but say in gen 7, we get 15 super threats, 10 that aegislash can stop, 5 that aegislash can't stop, but greninja can stop those 5 threats, so by the logic of this suspect, we bring back greninja, a borderline broken threat to check others (PS, I know aegislash and greninja aren't the same at all, its just an example). But if we go down this path, we will most likely either reach a point where we run out of borderline broken stuff like greninja, deo-d/s, gene, and aegislash, and the threats keep piling on, and then matchup isn't fixed, or we get a really centralized and unbalanced metagame, built around 5-8 huge threats and countering them, sort of like how ubers is about primal groudon, extreme killer arceus, xerneas, and beating those threats (I also know that isn't what ubers is about, but those guys completely centralize the tier, and if you don't have generally 2 solid checks to each, you will lose). Anyway, unbanning aegislash won't cure matchup, it'll just keep it from coming back for about a year.
TLDR: MATCHUP ISN'T GOING TO GET ANY BETTER AT ALL, STOP WHINING ABOUT IT! AEGISLASH MAY BE A SHORT-TIME SOLUTION, BUT IT WON'T HELP IN THE FUTURE.
But like I said I'm not convinced at all about this match up argument so I'll be voting for Aegis to stay in Ubers.