Invulnarability while recovering would be nice, yeah, but not after you've recovered. The second you can move again I think it should be fair game to kill you, because there are tactics you can throw into advanced melee immediately after exiting battle, and it would slow things down if you had to wait a second to hurt each other again. There is enough invincibility as things are in advanced melee. If somebody is charging beams try to go for hard hits to smack your opponent away from you so that you have more time to get out of the way.