We've already established that tornado generally wouldn't be a smart attack to use,
No.
Your argument is that Tornado can be SDI'd out of and D-aired, therefore punished. My argument is that good MKs position themselves with the tornado to make it harder to SDI and punish, drift to chase you DI and keep you in longer, or drift away to avoid punishment altogether. Fox has no special tool that can bypass this. Tornado is still a very good tool against Fox, sure the top center of tornado isn't safe for him, but against a majority of characters, it isn't, so MK usually doesn't do that.
and shuttle loop and glide attack are punishable by dair or upsmash.
Shuttle loop is not punishable on reaction by D-air. The problem with this is, if you predict a shuttle loop and D-air, MK can easily just U-air/N-air/Tornado in the same situation. He has multiple safe options in a given situation, more than Fox does.
Glide attack is punishable by D-air, U-smash not really. Only if the MK spaces it badly will it be punished by U-smash, which, if you're assuming both characters are good, at a high level of their metagames, and know the match-up well, won't happen.
The only things I see that MK has going for him against Fox are his aerials (which there are ways around; you won't get it every time simply because you're in the air with Meta Knight),
Vague, general statement.
his grab, and dsmash. Someone said something about MK's ftilt earlier. All you have to do is shield it.
Given that you're in a position to shield it. You can't automatically shield whenever; if you're in any type of lag at all, you can be punished with an attack like F-tilt, D-tilt, D-smash, Tornado, Shuttle Loop, etc. Also, good MKs won't follow up with the F-tilt when the first hitbox hits your shield, making it virtually impossible to punish unless you perfect shield it.
And if it pokes you, your shield is too low...generally works the same way for every character in the game.
Not pokes as in pokes your shield. Pokes as in uses safe attacks out of your range to build up damage. Case in point, D-tilt. It's fast frame-wise and difficult to punish even if it hits your shield. It outranges all of Fox's grounded options, and it's quick enough so if Fox decides to jump, MK can perform another attack before Fox hits aerially.
And if MK approaches you, then mindgame him with Fox's speed, maybe a surprise attack or grab.
Generic blanket statement that can be used for any character in any match-up. Statements like, "oh just mindgame them," are really bad in match-up discussion. Samus doesn't beat Diddy because, "oh just mindgame him away from his bananas and use them against him."
There's a difference between "mindgames" and "mix-up potential" (probably not the best wording, but whatever. Saying, "You can mindgame out of something," is a baseless statement that doesn't much worth of it. However, saying, "You can mindgame or mix-up out of something because you have 5 options in this situation while your opponent has only one," is a little more valid.
With that said, how exactly do you mind-game MK with Fox's speed? Are you implying that Fox has quick, good-range pokes or powerful smashes that are frame-wise fast that beat MKs (which he doesn't) or are you implying that Fox is so fast that your opponent will be confused (which they won't, Melee anyone)? To be completely serious, Fox's ground speed doesn't mean much in CQC, by the time it takes you to dash away, MK could have D-tilted, D-smashed, Shuttle Looped, or chased with Mach Tornado.
Don't forget Fox has an illusion if he needs to get away from an unappealing situation, but use it with discretion. .
Fox Frame Data said:
llusion
Startup: 20
Hit: 21
Hitlag: 5
Landing Lag 25
Total: 61
Shield stun: 9
Shield hitlag: 7
Advantage: -63, -38 if on the ground
It's a linear, punishable move that isn't good frame-wise. It's better for recovery because you're much farther from your opponent on activation of it, but for retreating on-stage?
The problem I'm seeing is that people are throwing generic blanket statements like, "Fox has the speed to get away from MK," or "Fox has improved a lot over the past couple of months, so the match-up should be better." The former is bad because it tells nothing of the actual match-up, the latter is bad because it's assuming that MK hasn't improved at all over the last couple of months, and assuming that overall character growth is large enough to propel match-ups one way or the other even if the match-up is still skewed.
People are also considering situational things way too often. Fox's D-air beating the eye of Mach Tornado and Shuttle Loop has turned into, by some, "Fox beats Tornado and Shuttle Loop to the point where MK shouldn't use them much at all," even though the chances he'll have to punish either is slim, and he can't punish all uses of either.
And this question still has yet to be answered, I don't feel like: What do you do when MK decides to approach? What do you do when MK just starts poking with D-tilts and playing extremely safe but still racking percentage on to you? Fox doesn't have many defensive options to stop MK's offensive game. I feel like this question has been dodged the entire thread.