It's REALLY debatable V! Hilde is going to be the defacto fire healer for HMS, especially for pubs, because 1) she doesn't cure stuns 2) she only has one heal in her base kit, 3) she has far less healing potency even with a better co-op ability and 4) energy stacks gets removed when you're afflicted. I think she has her place and might be optimal for teams like 3x Mikoto's or Mikoto/Euden/Vanessa where everyone has stun resistance, but it remains to be seen how well she performs with sleep resist characters like Ezelith, Naveed, and Sinoa. Sinoa is especially relevant because Sarisse/Sinoa is an insane clear combo, made potentially even better with the fire husbando so Vanessa isn't required to always survive roulette thanks to his wind resistance. I think V! Hilde will still be good, but potentially more as a side-grade to Verica than a flatout replacement, especially if you prefer pubbing over pre-mades. If D! Cleo has proven anything, it's that 5*'s limited's aren't always created with the intention of being the best for current endgame content.
On the topic of her being a fire healer, I think it's fine, because right now Verica is the only fire healer for HMS, the content the majority of folks haven't even cleared yet (Lowen and Hildegard also have confirmed clears, but that requires max whaling). While 4*'s are more likely than 5*'s, it's still completely possible some people still don't have Verica since she's never been on rate-up, and that just becomes more and more likely for newer players as more 4* adventurers get added.
Personally, I love Verica, but after MUB-ing HMS and slowly working on the Fafnir Wind Statue, I'm looking forward to having a different adventurer I can use to heal for HMS. Also, if they're gonna add another water healer for HBH, I'd rather it be a permanent addition to the pool rather than a limited. It's WAY more likely a 5* water healer will be a straight upgrade to Thaniel who has a fairly sub-optimal kit compared to Verica who honestly is overkill with how much healing she does, so restricting that water healer to being limited would not be ideal.