She has gained resources to deal with those things in the end.
The main reason hp refill enemies were a counter to her in the first place is you had to stop simply blowing everything up and consider how to take the next hit and go from there. Even before she obtained her ultimate, Dark Metatron was easily capable of defeating Athena- where almost every enemy had a hp refill, and the first enemy would destroy you before you could take a hit. She didn't even need a majorly changed team- she just needed to rethink said team a little to deal.
In short, most of those counters were 'counter's because people still wanted to just punch them to death. Those are what changed Dmeta from a team that was absurdly powerful and could easily do most content in the game almost brainlessly to something that required thinking. And even then, a lot of it took a while to fully start unloading itself into the game. Dmeta dominated for a long time and people will expect her to dominate in the same fashion is what i'm getting at- I'm worried, and expecting, that players will expect the early ages of DMeta where she dominated in that fashion, despite the fact the game has changed thoroughly.
And it has changed thoroughly, yeah. That's why I feel she kind of needed the sub pool expansion and the HP buff to keep her validity in the meta alive. And yeah, I'm aware those were counters to keep her from demolishing, but in most cases, especially back then, it was hella fucking hard to come up with anything better that worked for her because her best subs were so REM-specific and you were kinda boned unless you had them. That's why I stopped maining her after a while-- I realized I wasn't clearing any descends with her because I lacked the resources needed to make her work.
This is really my main worry in terms of actual balance instead of playerbase, though. I'm not entirely sure how much of the game falls like dominoes to Dmeta nearly as much anymore due to number game- and for content like the rushes and C10, I'm almost certain you'll have to drop that mentality immediately.
I'm just not sure how impressive Dmeta's actual firepower is in the grand scheme of the game anymore. Especially as it has to endlessly deal with the existence of cards like A.Indians and A. Egypts slowly appearing more and more.
True, it's easier to achieve monstrous damage now from newer cards. In fact, she probably doesn't even hold a candle to a lot of stuff now. But she does have a TON of resources to work with now since she can use attackers AND gods since her ult, and her HP means she can stand to take more hits. Combine that with a DIza sub and you've got a much less glass cannon build and a much more tank build that has a lot of potential, especially since you'll be running with a lot of resist capability to keep you alive.
Meanwhile we've had ult Pandora, new ult Persephone, devil!Haku, and so on come into the game too, which can give rows and orbs for days. With just those three you'll be sitting at 10 rows which is a flat 100% more damage across the board, putting her at a respectable 32x damage (which is still further enhanced by DMeta's active). Still not up with the best of the meta, but you also don't have to fulfill any other requirements than "make rows" as long as you're in HP range, unlike AIndians who need heart combos or combo count, or AEgyptians who require matching or combos. (And even then comparing an ult to an Awoken is kind of an unfair comparison because Awokens are kind of ridiculously great by default and require a lot more work to put together). DMeta has always been more of a "get hurt and GO GO GO KILL OR BE KILLED" kind of style and I'm happy they're taking steps to make her more usable in that sense, especially since I've not used her as a lead for ages (even though she's a fantastic sub on many parts!).
I can see her being able to handle rushes and c10 now, and I never would have even thought she could before. Just balance your orb changers and stat sticks and go for it. Thinking harder about it, putting two DIza on your team would take away some of your punching power, but at the same time, even without +99 HP, they'll straight up give you 17151 HP at max level with DMeta's HP multiplier, and a perpetual 35% resist (45% to dark with DIza's resist awakenings? I dunno how the math works between skills and awakes.) making it last even longer. That's insane-- back in the day when I mained DMeta, I struggled to have that much HP with my
whole team (of course I can top it NOW but yeah), and there it is with two units out of six. And taking that into account, maybe having her recovery awakenings won't be as disastrous as I originally thought-- that's a LOT of HP to cover.
There's a lot of potential here if you play your cards right. Especially since you'll be working with Osiris-tier HP, who can handle stuff like that with 12.25x damage and TPAs. (granted, he also has huge recovery capabilities, too, and you don't want that on DMeta, but still).