Fixed the chart. Thanks.
Yeah, 18th level is a bit long to wait for Freedom of Movement. But note that the Scout gets it at 18th level as well, and that Tome of Battle classes in general don't have amazing base class abilities, because they're getting fully scaled maneuvers and stances. For example, the Swordsage only gets Improved Evasion at 17th level, and nothing at 18th or 19th. Past Mettle at 13th level, the Crusader gets nothing but more Steely Resolve and Smite uses. And the Warblade gets his Int to AoO at 15th level, a bonus Feat at 17th level, and nothing at 18th or 19th level. I don't want to make the Vanguard too powerful compared to other ToB classes.
Take a look at the first level stance, Momentum. Through movement, it allows you to build up a bonus (up to your Dex modifier) to all damage, Bull Rush, Disarm, Overrun, Sunder, Trip, breaking item checks, Escape Artist Skill checks, and on any opposed check made to physically push or move an opponent or resist such an attempt.
So if you choose to use this stance, your bonus to most opposed checks will be 1d20 + size + Str + Dex + Feats + weapon properties + magic items. If you specialize in any particular check, then that's likely to be a very high number. And it won't just be for certain maneuvers (like Setting Sun) but for all such checks (for example, if you use Knock-Down or Knockback)
You're correct that Lightning Fox does have a fairly limited play style - you can move around very easily, Bull Rush/Trip/Overrun (with fairly effective bonus damage), and avoid attacks (there are a lot of counters). But when combined with other Disciplines, I've found that it's really quite balanced and fun.
But perhaps you are right. Do you have any specific additions you think I should make to round out the Discipline and make it more flexible?
Thanks a lot for the feedback. It is truly appreciated. If there are any other ideas or edits, please let me know. I'm still very much open to changing stuff around.