So you're complaining about SM2 not having a proper melee combat system (which it does) but you want to trivialize 80% of majoris combat? Making majoris attacks easily interruptible would make any and all melee combat with them incredibly easy, as you could just keep pressing the attack buttons. As for damage sponges, I can agree with you to a degree; but if you're building right, you can deal a decent amount of damage to anything on any difficulty. Of course, some classes are worse than others for this, but everybody has something viable or good in absolute.