1. In future DLC or updates (voice actors willing), more announcer/class lines for certain criteria during a match as usual. Makes the environment fun and thriving aesthetically. 2. Possible cosmetic items for classes that can either be purchased for a high price or earned via milestones. 3. Ability to change the number on some of the Pros' suits, just to add a little customization. 4. More maps. Of course this goes without saying. 5. New or Customizable taunts. 6. New Protags in future updates.
This is pretty much the same stuff I'd like to see. To put it simply: More content is going to keep people coming back, more ways to spend $$$. Obv. the devs should (and will) focus on balances/bugs first, but the above list has a good idea of ways to expand the game without breaking the balance.
The numbers on the suits are only 2 digits, so 420 and 666 wouldn't be a bother, and some people use 69 as an actual jersey number instead of an innuendo.