This game is less competitive than smash 4, and is closer to brawl, than it is to melee.
The airdodge changing mechanics are not a good thing, it gives the characters in disadvantage too many options. Previously if you used a move like marths fthrow, even though it didn't combo, it would put the enemy in an uncomfortable spot just in front of marth where they need to jump, airdodge or attack and they have to instantly make their choice where marth can either continue the string or just restart it with the correct guess. It was most definitely a guess since no one can react at that speed. Now, the defending character has an additional 2 options with airdodge left or right. Again, if they choose these options the marth player can not react in time, they have to predict it. It is impossible to regularly string together, or condition an opponent when they have 5 options.
This applies to countless things in the game, like landing options where the enemy used to be able to dair, fair/bair, b-reverse something, airdodge or just nothing. Now there are 2 more options with the directional airdodges. Juggling has become WAY harder thanks to this and even the characters with the worst landing options (like DK) have 4+.
"But one airdodge makes juggling easier!"
No it doesn't. In smash 4, only a handful of characters could get away with multiple airdodge cheesing, Mewtwo and Jigglypuff the most notable. The majority of characters just faded away to a ledge or b-reversed stuff. Juggling would have been made easier if you were only given one airdodge and no option to move left or right, but those extra 2 options have made it harder.
Edgeguarding is a different story, and is absolutely easier with the airdodge limitation, but thats it. Is the trade off worth it though, much easier edgeguarding for a severe crippling to strings/combos? I don't think so at all. I wish there was just the one airdodge limit without the directions.
And I haven't even talked about hitstun yet. Universally reduced, much less attacks combo than they used to. Countless characters have lost combos from smash 4, and some characters have lost A LOT. This is simply because of less hitstun and how knockback is gigantic on hit, but slow down. This means that attacks that used to have that property of putting the enemy at an uncomfortable distance, now send the enemy away really far, really fast before any follow up is possible.
Smash generally has 3 types of attacks, the low-knockback obvious combo starters, medium knockback moves to trap the enemy (think of dtilts that will pop someone up on a battlefield platform but don't combo) and obvious kill moves. Those medium knockback moves now send the enemy so far, so fast with so little hitstun that they have full access to their defensive options too quick.
Ledge mechanics are lame, hardly any tricks are possible and the invulnerability of the ledgegrab seems to be freakin monstrous.
The loss of running cross ups might make sense from a logical point of view, and having it in the game to begin with has likely skewed out perception, but its frustrating to lose that option.
The game is slightly faster and attacks do more damage, thats it. People who talk about 'its a brand new engine!' need to learn what an engine is. Its the exact same 'engine' as smash 4, characters just have faster run speed and airspeed.
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I love the smash series, played each religiously and spent too many hours of my life on this forum. No amount of fanboyism is stopping me from having serious issues with the airdodge changes.
I believe the game will be more interesting and fun to watch than competitive smash 4 purely because of how repetitive, boring and obnoxious the top tiers were in that game but this game is far more about 'neutral' game than it is about advantage or disadvantage states and for that reason, its closer to brawl than melee.