hmm...
K F1ZZ, what I saw most that needed improvement was use of UpB. Minus the wrong button john (cause human error always pops up).
Now correct me if I'm wrong, but the Brawl+ you where playing allowed you to attack right out of UpB. I saw this once at the end of the vid. Then there are other times your freefalling. So I dunno.
Anyways, More or less how you used UpB is convenient, escaping some dooms with a little extra range. However, you have more control with UpB then you give it.
Instead to curving upB and falling some to avoid attack, try using the C-stick during the UpB animation to make the angle moved more clear-cut. It will give you a straighter angle and because of which more distance gained instead of lost due to a curve.
And Try to DI higher. Lucario has a great jump distance, and as said half the time lucario shouldn't have to use his Up-B to recover. If you can, try to limit the amount of times you do use your Up-B to jumping etc.
Also Up-throw + insert move here. You tired a Up-throw to Nair a few times, which worked some of the times, but towards the end, your opponent (PAUSE) could predict your next move (being the Nair). I suggest that you try a different move, Like uair, or just plain not attacking to charge a useful in the future AS.
So switch your favorite moves around a bit to keep your opponent on his toes. Elsewise he's going to counter you more.
I also want to say to shield and tech more, but those depend on the type of play you choose, ( shielding + teching more would make you more defensive)
And overall pressure. You rolled a good amount of times, which they did keep you safe, but there where sometimes that a big O' AS would have done the trick. For example baiting them to shield with an AS, then dash grabbing them. If you can keep pressure while keeping your placement, then you'll be solid.
Side note, don't Dair so much. This is a habit of a lot of lucarios, and the more they use it, the weaker it gets, ruining the chance that when it could of killed, it didn't. Time the Dair's better.
-t2
*Edit
Other then that, its a good hearty lucario, and you know how to pull some of his extra quirks. Good timing too.
And the MK's recoloring looked pretty awesome, props to his recolor.