My current Casters include Merlin, NP2 CasGil, and max-level Hans. Would adding Waver to the line-up be a huge quality of life improvement? I know Waver is a godsend for farming, but how important is it have your own Waver?
Similarly, pretty much everyone says Tamamo is the linchpin of Arts teams. I've used her a few times, including during one or two Camelot boss battles. While it's a fun team and I kicked some KotR butt, I've found that my Arts damage dealers (Archuria and Chloe) also fared quite well when supported by some combination of CasGil, Hans, and Friend Waver.
I apologize for asking what is essentially another GSSR question. I'm not really asking about which banner to pull on, just about how crucial the Caster banner is. On one hand, I don't have Tamamo, Waver, or Sanzang. On the other hand, I already have decent Casters. And there are Servants on the other banners I really want (Namely, Enkidu and Cu Alter. Though I'd have a 66% chance of getting someone else, which wouldn't be a disaster but would be disappointing).