My experience with Hero's DownB :
TL;DR : Not as bad as I originally thought, but WILL still change games depending on what you get. The RNG spells I feel won't affect a game much, which is good. But it's still kinda bad.
General Mechanics :
The menu comes out Frame1, but you can't start a move until Frame20 (you can select it but it won't come out until F20).
If you cancel a menu, you have to wait 40 frames for it to disappear and allow you to get another one.
On the ground, you can cancel it with roll, dodge, and shield. You can also press shield for less than 3 frames and be able to move freely (similar to Lucario)
You can reverse the spell you want to use by holding the direction before selecting your spell.
You can't use the menu during hitstun. Any hit will interrupt the menu.
You stop gaining 1MP/sec during the thinking stance.
The menu disappears after 8 seconds if you didn't chose anything.
I'll now talk about the moves which can be used via command selection.
The Good ones :
Magic Burst : Probably the best spell ever. The hitbox is INSANE, can 2-frame or edgeguard for free, might be good at ledgetrapping as well. Uses all of your MP can scales with the cost, can kill RIDICULOUSLY early and deal up to 60%. The spell you almost always wanna see.
Acceleratle : Gives the Hero an insane mobility, which he can use quite well with large hitboxes. Gives him a few confirms from grab, mostly d-throw f-air which will kill at the edge at around ~100%. Lasts 10 seconds. Can be hard to manoeuver, especially offstage, since UpB is strictly vertical. You take more KB during the spell according to the in game tips, which can be good or bad.
Flame Slash : As with most spells, it's frame6 after selecting the move, which is standard for releasing a projectile, but for a slash this big, it's really quick. The range is (again) insane, it can 2-frame, it can cover every option during a ledgetrap (with different timings), deals close to 30%, will kill at 65% at the edge. Can be used to shut down any approach when someone wants to contest your command selection.
Kacrackle Slash : A worse version of the Flame Slash. But at low %, freezing can come in handy (it lasts very long), and if you 2-frame with it, they can bounce on the stage with a pseudo stage spike and end up in a terrible spot. Still very good.
Heal : Highly overrated, can only be used 2 times per stock (22% / stock isn't that much in Ult), not very fast so except between stocks, it will be very rare to use it. That's still a heal, and we take those. Overall decent move.
Bounce : Can auto-win you a match-up. Either broken or useless. Since it doesn't really take any slot, it's really good to have in your toolbox.
Oomph : Very good buff. Will make you hit harder and have more knockbac. The game also says (defense down), so it's probably a double-edged sword (but a good one). Seems to last a bit more than 10 seconds, like 12.
Psyche Up : Only use this to KO, the damage increase is very low.
Kaboom : Amazing projectile, will have a huge radius upon exploding, deals a lot of damage, kills super early, big range. Only drawback is the very high mana cost. Can 2-frame if you use it from center stage. Bang is its "pre-evolution".
Sizzle : Similar to Kaboom, except maybe a bit worse? Sizz is it's "pre-evolution".
Snooze : Don't think this needs explaining. Far from being broken, but it's good.
Zoom : Pretty good mix-up... If you're lucky enough to have it while recovering... Doesn't put you into freefall, so there's that.
The bad ones :
Kaclang : Has a hitbox on the way down. That's it. Easy to punish if you know the timing (30 frame window). Except relying on MU inexperience, I only see this being used during the last seconds of a time out.
Metal Slash : Deals 1% with low knockback and bad frame data. Never use this.
Hatchet Man : One shots the shield and kills at 40%. But really slow, and considering it comes from downB, I don't really see how it'll be used outside of a shieldbreak punish?
Kamikazee : Very slow, not even that powerful, can apparently be teched? You lose a stock for free, keep it for FFA's.
The random ones :
Whack : A projectile that can one shot. Needs to know the numbers, but this seems incredibly out of place. Low cost, too.
Twhack : The "melee" version of Whack, but with still a big hitbox. Seems to work very well at high %. Again, I hope the numbers are very low at low %. It seems pseudo reliable at 100%, I guess it could be used for shield art Shulk, but considering the high cost (30 MP), there are better moves. Can 2-frame.
Hocus Pocus : Oh, god. This move is bonkers. Gives you some crazy status buff or debuff, or just uses a move randomly. Thankfully, it's already pretty rare for it to show up, and it seems to have at least as many negative effects than there are for positive effects, which means we're unlikely to see it being used in competition. But it could be used when you're at really high % and your opponent just respawned. If it's very rare AND the Hero is balanced (which I think he'll be), I can see it being as hype as a G&W 9. Still don't like the concept.
I think the Hero's DownB is really interesting and will reward quick thinking and experience with the character. I'd not treat his downB as 4 chances to have a good move, but I'd rather look at it as a whole. For example, if you have some good buff spells but you also have a slash attack/projectile, you can bait your ennemy to come and then pick the offensive attack at the last minute to stuff their approach.
In the neutral, I feel like it's pretty hard to use, due to both the menu being slow and because it's hard to analyze all spells and quickly pick one. But for instance, after sending the opponent offstage, you can position correctly and use DownB and choose between Magic Burst, Flame Slash, Kacracke Slash and Twhack (in that order) to 2-frame. Or take any buff if there's none. Or just cancel the menu if nothing's interesting.
This is a very high skillcap move, so we'll have to wait for a few months for it to be fully mastered. It is really cool IMO. I just hope the Hero is average and not a good character, otherwise he'll receive a lot of hate lol