Hrmmmm....nice. A few suggestions (...for now, might think of more later...) regarding the wording for Force Wave Slash, I'd personally word it as follows:

A Vorpal Warrior may take a penalty on attack rolls to increase the reach of any slashing melee weapon she wields. She gains +5ft reach / -1 penalty, but she may not take a penalty greater than -5 for this ability.
I would word it this way to avoid confusion, since melee weapons don't have range on the whole (reach and range are rather different) and it currently fails to state (as I assume it is meant to) that the ability only works on slashing melee weapons, since that's the flavour of the class. As it stands just now, the class could take a -5 penalty to attacks and increase a longbow's range by 25ft (which isn't the intention I believe...)

Also, there's an edit issue here (in bold):

Snicker Snack(Su): In the hands of a Vorpal Warrior any slashing weapon gains the vorpal quality. If the weapon would gain or already has the the vorpal quality then this ability grants the blade grants the weapon the keen and speed enchantments instead.
I'd stick with the Keen and Speed thing on Snicker Snack btw, since it fits the fluff/base material somewhat better than Pounce (even though I agree Pounce would likely be a more useful effect).

Probably a good idea to add class levels (or maybe half, as anacalgion suggests) to effective fighter level for the purpose of attaining fighter bonus feats too, and I'd personally make a note that you may only take feats which apply to melee slashing weapons with the bonus feat choices here, but that's just my opinion and certainly not a necessity.

Feel I should chime in on the 'not using BAB for calculations' argument too, as Debi says, HD is more than sufficient for this purpose and has far less issues.

Otherwise really good piece of work, and FINALLY something which makes Vorpal a little better than a 1 in 30(ish) chance of doing anything significant. Have a cookie