Ironically, I noticed the Brawl- forums were drawing a blank on breaking Marth, so I thought up some ideas of my own (at least for Dancing Blade):
-DB1 should be dramatically increased in hitstun, to the point of actually comboing into things like grab, D-smash, and perhaps aerials if Marth performs it in the air.
-Dancing Blade's counter tends to be its punishable nature on shields, so I thought of some traits to its individual hits to make Dancing Blade diverse and even more difficult to deal with:
DB1: included above
DB2mid: Nothing really except shieldstun, to keep the opponent locked inside his/her shield if applicable, probably increased damage as well. (Most of dancing blade's hits should have increased damage)
DB2up: Same as DB2mid, with slightly more knock-back heading upwards.
DB3mid: This hit will have more range, and will actually have knockback comparable to the original DB4mid, only with a set knockback for the finale.
DB3down: High shield damage, so the DB4down will certainly shield-poke, if the opponent had very low shield at this point, the shield will break.
DB3up: Should have significant upwards knockback to set up for a potential DB4up tipper, higher hitstun so you have time to consider what finale to use depending on opponents DI.
DB4mid: The actual damage and knockback might be raised, but the biggest change I have in mind is a fire slash projectile (that DB3 mid set up into) with some knockback, but this is mostly for damage purposes rather than getting the kill.
DB4down: Should be harder to DI out of, but not impossible. (The hitstun for the individual stabs should be high so if they do DI out, it isnt easily punishable) It should semi-spike, and perhaps even give a flower condition out.
DB4up: This is where the attack kills. The only change made to this should be a windbox heading up and forward. This attack shouldn't kill as early as 60%, but at the same time the reward for setting up a tipper for this attack should be extravagant. The windboxes heading forward should blend well with DB3mid's set knockback.
I liked the idea of Shield Breaker breaking shields 100% of the time, maybe increase shieldstun so that even a perfect shield stays out long enough for another Shield Breaker to hit?
Brawl- looks awesome by the way, I can't wait to see the finished product.