ZeRo said on Twitch the other day that Marth is the bottom of top tier (A) - which is just one character spot higher than where I would say, being the top of high tier (B)
I think ZeRo realized he was over rating Marth/Lucina when his Lucina failed against Ally after a few attempts, but his Diddy pulled off the big wins.
Could be the former, but as good as ZeRo is, his Lucina was nothing on his Diddy. Sure his Lucina is very very good, but to be honest, it was only about as good as his Cloud. I really think his Falcon is better in general.
I understand his thought though; it's wise to pick a character with a good MU if your main is struggling. Doesn't mean you'll win though, because at the end of the day, your main is still your main, and you're going to do so much better with them in general.
But I noticed with ZeRo's Lucina, he claimed he wanted to use her for "consistency" reasons, yet most of the times he never capitalised on this point. There were times I saw him trying Leo style ledge trapping and stuff, and while stuff was working, the opponent was surviving until percents past when Marth would have killed because Marth's general ledge trapping game is strictly more rewarding due to how Jab's angles work (easy tipper Ftilt), and the general distance you are looking to space yourself from the ledge (tipper Fair/Nair range).
His aerial spacing game is generally quite good, but it upsets me because when I see him space Fair well near the ledge consistently at like 100%, I'm like "why don't you just use Marth? - that would have killed".
He very rarely killed anyone with that fabled Fsmash read at 80%. He was just playing Marth for the majority of times. I'd be very interested to see him use Marth. That, or if he's going to use Lucina, play her more like Lucina, and pressure a little more.
One of my friends in my area used to use Marth, same as me, but we have always been noted for having differing playstyles. He plays rather aggro, trying to pressure the opponent, goes for strong edgeguard reads etc, where as I play a much more passive, defensive spacing game, walling the opponent out, trying to keep them at the ledge etc, trying to take as little damage as possible. The way we played, I always did better than him. However, he's recently switched to Lucina and he's started doing much much better with her. The way he plays translates into Lucina better than with Marth; his ability to pressure shields is better in general. He goes offstage deep for pressuring edgeguards and succeeds more often. In a similar fashion, my Lucina, whils still solid, is just not as effective as my Marth. When I'm walling somebody out and keeping them in a corner, when I land that tipper Fair at 100%, I'm happy when it kills. I notice when I play Lucina there are far more times I think "damn, that would have killed if I was playing Marth", far more than "Okay I'm glad I'm Lucina in this situation".
I honestly just think ZeRo would have done better with Marth by the way he plays.
It's for this reason I always used to say Mr E would have done better with Lucina, but as of late, he's kind of transitioned into being a bit more patient and its good to see.