Even though I'm optimistic about the new guest character (yeah, the trailer felt lazy in terms of content (especially Nightmare's appearance at the beginning), plus the graphics were not the best, and yet I rewatched it I don't even know how many times because of brilliant music, mesmerizing battle with Mitsu and beautiful action), putting him on the cover alongside Mitsurugi (without adding anything/anyone else) seems unfair to the rich SC story and its universe with numerous uniquely designed characters.
I've always considered the battle between good and evil, Soul Calibur and Soul Edge to be one of the key aspects of the game (of course, it's partly an oversimplification). Even in SCVI you apparently keep dividing characters on good, bad and neutral ones, judging by their aura during RE and weapon glow during Soul Charge. And these two extremities have always seemed exciting to me, with each character having his/her own reason for being on this/that side or even being misled due to certain circumstances, which is why putting only two neutral characters on the cover is kind of a let-down for me, as it does not represent the core element of SoulCalibur.