Rollback to late 2016, redesign of the matchmaker (also make it 100% transparent), improving the competitiveness of this game in terms of servers, anti-cheat (especially how to deal with detected cheaters) and netcode.
The developers have to decide whether the game is intended for players who like to play with friends who live on the other side of the world, or if e-sports is the main focus.
In my opinion, there is no room for compromise at this point, although there are perhaps some engineers and mathematicians who can do a lot of trickery in this regard.
If the game is on a high quality level in the mentioned areas, I would try to make the game E-Sports-ready.
Blizzard should be a leader in e-sports, but I don’t see that happening right now.
In the longer term, a way must be created to keep players in the game. Lootboxes with the current content are not sufficient.
Blizzard could possibly learn something from CS GO.
I don’t think Jeff Kaplan has to pay off his student loans anymore. 