Well, from what I can tell, to solve Marth's anti-CCing problem, you're more than likely going to need to redevelop your style of Marth.We know CCing eats all his attacks alive, players have been trying to compensate for this with his DB wich in my opinion, is bad (now I'm not trying to sound like an expert on Marth here, I'm just trying to give some personal exprience that may/may not help you), as his DB gets him CC punished just as much (first two hits)
Well, what I've been doing recently (I actually just kinda started playing Marth more seriously), is I've actually been putting more of a focus on his aerials and his d. tilt.
These are the aerials I focus on with Marth :
F. Air: Means of approach; grab and F. smash setup
N. Air: Means of approach; means of retreat; grab setup
D. Air: Combo enabler at higher percentiles
Nuetral B: Means of approach; means of retreat; edgegaurd enabler
First off, most players usually try and link grabs with F. air at low percentages. I've learned that's a big no, no.
After a f. air, I usually go for a shffld' n. air in order to avoid the inevitable CC retaliation. When that lands, I go for a grab as it gives a bit better knock back and stun than f. air and this usually throws people off their CC game.
So a common string for me at low percentiles is:
F.air>N. air>Grab.
Linking F. air to grab directly is MUCH safer at mid percentages (40-50).
I use N. air a fair bit more than F. air though, for the reasons previously stated, and the fact that it's not as sweetspot dependent as the rest of his aerials, so Marth can space it and still get away with more.
D. air I use quite a bit differently than most other Marth i use it as a tech chase starter
I use it at higher percentages, to go for f. smash and grab and tech setups. I never shffl this move. CC'ing owns this move more than any other aerial, even at higher percentages because it's extremely difficult to sweetspot this move shffl'd (you gotta be like, right next to em')
So instead I SH and L-cancel it. When it lands it pops them into the air for all types of setups. Try it out and see if that works out for you. I dont FF
Lastly his d. tlit.
I seriously don't believe players use this move enough. I ***** this move, as It's godly in my eyes. It's hard to CC this move as it's so quick and sneaky it tends to be hard to anticipate (unless you have specific setups for this move that you abuse). We all know it leads to combos like crazy and I actually use this move just as much as f.smash and nuetral B for edgeguarding
SORRY FOR THE LONG POST
what i am trying to say marth has the most melee range in the game he should not be hit
there must be something you are doing wrong as a marth community we need to find a solution