Grinding the crack only really let's you improve with using the system mechanics for sure as those are unlikely to change at all.
But I expect pretty decent character changes once it's released, especially if the demo is any indication. Also a lot of the grimy characters that are gonna be good early aren't in the beta, like the grapplers/zoners. Lots of people are gonna lose to unfamiliarity if people are playing blanka, JP, Sim, Gief, manon lol.
All that grinding just to loose to day 1 and week one characters.
Ryu is probably your most solid bet against all the foolish early on, he looks complete. If they don't nerf him more from the demo he should be pretty upper mid tier at least.