Ike / Fire Emblem Discussion? Let me weigh in on a few things...
Corrin:
Along with counterplay, Corrin received these subtle nerfs to his mobility:
- Walk Speed: 1.2 -> 1.15
- Run Speed: 1.5 -> 1.45
- Air Speed: 1 -> .97
It doesn't seem like much, but run and air speeds were reduced to Ness levels, but with average aerial acceleration. Corrin's defensive ground movement is still awesome with superior dash->shield and average fox trot frames, but Corrin has less control over space than she would like. SideB also has worse frame data than once thought and recovery is merely average or slightly above.
Corrin still has a lot of great things, but once you play people, you have to put in quite a bit of work for the win. Corrin's still great, but he has to work more than what was previously thought, and that mobility can be used against him.
Marth vs. Ike:
Marth is probably better than Ike. He is just more well rounded vs. more of the cast. Ike has more volatile MUs, reminiscent of DK and Bowser due to the way they all punish and fish for grabs.
Ike's worst MUs are:
(uphill neutral)
(uphill neutral)
We know it's Ike's disadvantage:
(zone breaking, strong kill confirms)
(dangerous gimmicks, zone breaking)
(zoner + grappler mixed)
(out-rewards, good vs single hit characters)
Even Ike's worst MUs are "heavy MUs" where Ike can still obtain occasional confirms and good reward when the opportunity arises, since he can frontally combat most hitboxes directed at him if read.
Probably Ike's disadvantage:
Most zoners depending on how you look at it,
(dangerous gimmicks)
(out-rewards)
(out-tanks and rewards),
(zone breaking)
Ike is not good at lower levels of play and doesn't have as obvious a learning curve. Players will need to be consistent with some odd tech such as the footstool combos and dtilt->bair, combat walking autocancel quick draw, etc.
Ike with his fair buff a few months ago hasn't been explored much by the top Ike players (or only Ryo now) until more recently, and it was admittedly large to his metagame and viability.
Marth has way more rep at mid level, similar rep from high level mains, and way more rep from top players as secondaries (Ally, Leo, False, and Nick Riddle just off the top of my head)
Results that I know of (minus Japan):
Corrin:
Cosmic Cosmos wins almost every Texas Challonge that I see, he's dominant over there and I think this is probably understated. You see him as secondaries all over. Ryo can pull out Corrin for more favorable/stable MUs and take sets off players like MVD, though his overall results solo haven't been able to match solo Ike just yet, and has been used much better as a secondary. Vapour in Canada upset Ontario's Blacktwins at EGLX. John #s and other tristate people use Corrin every now and then as well.
Marth: Mr. E, Pugwest, and farther down the line due to split usage, False. Mr. E took a set off Nairo and all 3 continue to beat high level players. I haven't seen much of Pugwest outside of his region, but he can take sets off Marss and beat everyone else in his region. Also took a set off PikaPika where Mr. E lost.
Ike:
Ryo still beats many good players, though he is getting upset more often. You can still see him take sets off M2k, K9, or Scatt here and there, though it's not a consistent win rate of course.
There are some Hidden Bosses that perform decently in tournaments, such as Yoh and Jage in Europe, or Justice in Oregon.
Waldo from NYC has started to get more top 8 placings in his region and took sets from players like Marss and Pugwest.
I've been to a few larger tournaments recently, being able to take sets off of Pugwest, V115, Chrim Foish, and Holy, though the latter 3 have beaten me in sets before as well.
Rango still has taken sets off players like 6WX and reflex, does OK in his region.
It's consistent with other mid-tier characters, but Ike's average rep is still very low. Ryo is Ike's only top player rep right now with Ryuga gone and the rest below him getting decent/improving results.