If mkleo devoted himself to Joker and dropped Byleth, would he be able to once again perplex his opponents until he gets figured out again? Or is Joker more predictable than Byleth?
(Not knocking him, he dominated for years before he fell off ... and the sets between him and sparg0, reminds me of the old m2k vs ally days, lol.)
Byleth is relatively speaking pretty "bad" and I think much of Leo's current problems come from trying to invest time into Byleth. I don't think Leo's Aegis is bad. I think the enormous amount of time that Leo invests into Byleth is the handicap holding his Aegis back from reaching sparg0 or Shuton levels. Leo is too reliant on Byleth-style spacing, but Byleth is actually very exploitable at top level. Byleth is slow, Byleth is bad at getting off of ledge, Byleth can't land, Byleth has trouble juggling without insane air drift reads... It's rough to play Byleth. Leo makes it work against a field of -1 matchups because he's Leo.
I don't get into details a lot lately, but this time I'll dive in a little bit.
Once top players figured out the matchup and started avoiding the early KO traps, the big innovation that enabled Leo's Byleth to stay competitive was his use of f-air for undershooting in neutral. He was able to shut out Cosmos' Aegis at LSI and beat Sparg0 at Genesis 8 last year with this. I have no doubt that he picked it up from his reverse up-air spacing with Corrin when he started to play Corrin.
The undershot Byleth f-airs are really difficult to navigate for most characters because Byleth can follow up with d-tilt or jump n-air. It's pretty similar to Sparg0 standing in place and Cross-Slashing in anticipation of an approach. The Cross Slash covers so much space--how are you really going to punish it if he whiffs? Byleth undershooting f-airs is based on the same concept, but Byleth is a lot easier to whiff punish in this way because f-air is strictly horizontal and you can approach from above with various moves (like Cloud f-air).
Then the other issue is that Byleth doesn't have the mobility to threaten you if you just don't approach once he whiffs the f-air. So characters like Diddy with banana, or Wolf with laser, or Olimar with Pikmin, or ZSS with z-air can easily just... dash out of range of undershot f-air and attack Byleth at range. Byleth has to commit to a super risky dash attack to actually get these characters out of their zone after the f-air, or hope that they roll behind him.
People think n-air and up-b are Byleth's most important moves, and they're not entirely wrong in a mechanical sense, but f-air is the bedrock foundation of Byleth's neutral, and, unfortunately, Byleth f-air is starting to be really difficult to use against the field. Fast characters and zoning characters give Byleth a ton of trouble because they just weave around or ignore the f-air even when it's undershot.
So, what does Leo have to do to keep Byleth competitive?
He has to find a way to get more from CQC. Last year, spotdodge -> jab worked as an answer to Cloud aerials, but that won't work against the other characters that Leo struggles with. He's probably thinking about using more f-tilt in neutral, but f-tilt does not lead to enough reward in most situations to put the risk-reward situations in his favor.
It's rough.
Joker has more meta development waiting with Gun and would be the sounder choice. Even Aegis would be the sounder choice if a future investment is the goal.
But I also believe in Leo and think he'll make Byleth work as well. If I had to guess, his next big innovation is going to be more dash grab near corner at percents where IRAR b-air will kill. I'd also try more drift-away back-hit n-airs, since this puts Leo in a position to threaten b-air instead of the n-air sometimes (since he'd be facing away from the opponent), which is a lot deadlier than f-air at mid-high percents. Even if b-air doesn't kill, it does send opponents further away, leaving Byleth more time to set up an edgeguard.
lost 3-2 to Jakal
