If Akuma drops after the season 2 balance patch then does that mean season 1 dlc was really only 3 characters?
"Season" means more than one thing.
It could be the Pro Tour season. It could be a season pass of DLC characters. It could be a seasonal balance update.
In the past—with SFV at least—all of these things were roughly aligned. They are not exactly aligned now.
The first season of DLC characters, the Year 1 Pass mentioned above, is already locked in. We have a definitive time table that ends with the release of Akuma this spring.
The first season of the Capcom Pro Tour for SF6 ends in February, however. At least a month before the character pass is complete.
But the seasonal balance update is still a question. The Red Bull Kumite announcement suggests "Season 2" balance begins shortly after Capcom Cup. If that's the case, Ed and Akuma will be launching with "Season 2" balance despite being characters from the first "season pass."
Why are meaties weak in SF6?
I'm still relatively new to FGC so I don't know the nuisance of Meaty strength between games.
Relatively weak. On the surface they're just as strong as previous SF games, but perfect parry makes them a lot more risky to go for. Meaties typically leave the attacker in an advantageous situation, but going for a predictable meaty in this game can get you perfect parried into oblivion.