If anything, its a good idea to just go ahead and get Spica now. While having three Archers can seem overkill, Bashira does more or less get replaced by Nanaly once she gets CCd.

Plus, Spica when AW buffs other Archers so its not really a bad thing to have Spica on a team that relies on Archers for ranged DPS.

Until TP has an actual rotation of units, its a good idea to get Spica now while you can instead of when TP gets rotated and then you have to wait what feels like a year before it gets changed out again.