Don't really see a use to buffing boots/sword combo since the boots are made for use with the market gardener.
As I said, the sword playstyle uses the buff banner usually.
I'm not an experienced VSH player, but from what I know, the half-zatoichi is in a good place as-is. If we buff the health on hit, then it becomes harder for the hale to kill the player, and the hale is supposed to be able to kill anyone within 2-3 hits. Not to forget that the team usually has a medic too.
The boots are also fine as they are now, as peter said, they're mainly for rocket jumping/market gardening, and they fill that role nicely.