The plan was to balance the effects slightly over a 2nd level spell. Most Sorcerers gets a small situational damage buff at that level, so for the cost of a second level spell slot you get the same effect but for all damaging spells during a short duration. That felt fair to me. In addition, they do not need to be perfect balanced against each other since you can choose every time you pay for the feature which spirit you conjure. IMO it is more important that they fill their niche role then than that they are perfectly balanced against each other.
That is way too good though. That is just a lot superior to the spell shield. It is like 10 level 1 spell slots when you reached 13th level. Guardian (renamed it to protector since the subclass uses the spell spirit guardians as well) was aimed to be an alternative to shield but with a longer duration. When I was writing the subclass, I almost decreased it to +1 bonus to AC since I thought it might be too good as it was with +2.
They are not totally free, activating the feature costs as a second level spell slot and 15 feet is a lot less than 60 feet. I was comparing it to expeditious retreat and I think it needs to be better than that as half that spell is not worth 3 sorcery points. Changed dancer to take the disengage action and add a 5ft movement speed increase. That should solve the grapple escape atleast.