Originally Posted by
sanahtlig
Wind gets Seth, eventually. But most players won't have her til the 3rd or 4th Miracle Ticket.
Sol's main use is her utility, not her healing. Every element has access to a top-tier healer: Andromeda. Sol brings a ton of utility that most healers don't have, including a class C debuff that many elements need to reach the debuff cap (without Burst or eidolon effects). Without that debuff Sol would be little more than cannon fodder, as she'll have much less HP than all other team members in an off-element team. Therefore if that debuff isn't needed then Sol's usefulness is limited, and every element except Thunder already has an SSR healer anyway.
This is a simplified list of what the first two optimal picks for each element will likely be (doesn't include the 2nd Miracle Ticket, assumes you're starting from zero):
Fire: Amaterasu, Svarog
Water: Cthulhu, SSR Nike
Thunder: Raiko, Sol
Light: Sol, Michael/Raphael/Metatron
Dark: Hades, SSR Amon
Wind: Gaia, Sol or Titania
Sol is in a few of those, but she's generally low-priority behind that element's core SSR.