its your internet connection+brawl having a lousy online setup.
nothing is gonna get fixed about it, it is still the same as before, the only thing you can do to tyr and make things better is get yourself a faster connection, that or suck it up and get used to the lag. A big portion of it i can guarantee is your own connection, the other part is just indeed the fact that nintendo gave us a lousy online structure for brawl, one that they can't really fix, infact you're more prone to error codes popping up now going into random basic brawl's then originally.
if you truly honestly want to play competitively though, online isn't exactly the best place to go. And Basic brawl DEFINITELY is NOT the place to go if you are wanting to get better competitively. Go to some offline tournaments, you'll learn faster, enjoy yourself more, and have an overall better experience then going into online matches.
