IMO, 5 was visually and musically the best SC game, with some of the best costume design overall since 3 and a very impressive soundtrack. As far as the new blood went, I liked most of them.
Natsu was Taki with a less ridiculous physique, a cocky attitude reminiscent of Cassandra, and Kate Higgins' voice work was great. Patroklos was hammy fun (although A.Pat was a terrible idea) and let me get my shield-bashing in. Pyrrha was almost as fun, with O.Pyrrha being even more so, and Laura Bailey can do no wrong. Viola... if her design get re-used for Amy next game, I will never drop that game. ZWEI's moveset was interesting, and a better use of magic than Viola, not to mention a killer voice from Matthew Mercer, but was rendered poorly and his final moveset felt incomplete, with an underutilized stance that would have made him leagues better if he had in-move transitions akin to... well, everyone else. Only Leixia and Xiba seem to fall flat, but I kind of want to put that down to how incomplete SC5 is, being a straight carbon-copy of her mother with less emotional investment from the player and a lame running joke with a lot of failed potential.
I'd be impressed if SC6 was actually a continuation of 5 that works out the kinks and gives the fans a little more of what they want.