Having Lyn be a high speed fast combo Swordfighter would be a breath of fresh air (Roy comes very close but still), she could use the whole Sheik style of death by a thousand cuts, but at the same time reward players who can find the openings of their foes, and attack with precision and critical/massive damage.
If you had to imagine a trailer for Lyn what would yours like? Mine would be her coming in the nick of time, to back up the FE crew who're struggling to fight Ganondorf, stopping him just before he finishes his command grab on Roy. That or a character reveal with her protecting a defenseless person/character, in a town or city, which then leads to something like this...
It sucks when your favorite franchise is struggling to get back on its feet, even more so when they basically reboot everything, and leave out one of your favorite characters (Krystal).