I'd like that. 1k heartless fight was cool the first time, but it's gotten boring, having to smash through it in every playthrough. I still like the music a lot so it's fine but something like that would definitely make it more interesting.
Either they make them obligatory segments during the fight or... Wyvern's attack pattern is almost as infuriating as Air Soldier's.
It would literally be Chip Damage Hell letting them free alongside the other Heartless.
I would've actually liked the fight if there had been Behemoths and Wyverns. Don't get me wrong, I love the sequence that happens before the 1000 Heartless battle where you fight with the FF characters, LOVE that. But the solo 1000 Heartless battle itself is boring af. I'm not even sure why they bothered because it's just a time-waster, imo. Even fighting the hundreds of Rapid Thrusters on top of Pride Rock is more fun.
I would've been perfectly happy with the battle even if all the Heartless didn't appear at one time, but instead appeared in waves of 100 or 300. The wave-d battle in the final room before the Final Save in KH1, for example, has a 10th amount of Heartless and yet is sooo much more fun than this because it features Heartless that are actually challenging. I guess the 1000 Heartless was SE just showing off how much they could have appear in-game at one time, ultimately putting ego above delivering good content. Although I guess there's the possibility the decision had more to do with KH2's magic system being too much of a trainwreck to handle the added difficulty of KH1 Heartless without Donald there to give some back up Cures. And neutering Behemoths & Wyverns like they did Wight Knights & Soldiers isn't something I'd want.
I think it would be cool, but I would like the setting to change as well. The sandbox looks of the worlds in KHII aren't very accommodating towards things like the 1000 heartless battle though I understand the engine/hardware limits.