4Game

I'm a huge fan of both ability draft and professional dota, and I've always wished to see the two overlap. However, I completely understand why there has never really been an ability draft tournament: the game mode is simply to random and unbalanced for competitive play.
Ability draft has luckily been given a lot of love from Valve in the last couple years. They've fixed many bugs that affected both gameplay and visuals (R.I.P permanent floating moon glaives and the endless walrus punch steam). some of these changes went a long way towards making the mode more balanced, such as enchant totem bonus damage on ranged heroes no longer being applied to each projectile that is in the air before the first one lands.

Two main things still hold ability draft back from a more fair and competitive playing field, though. One is the fact that all heroes for both teams are completely random, and it can be hard to work with a lineup of Slark, Weaver, CM, Huskar, and Brood base hero models.
The second is that a great hero model paired with a great skill in first pick can often make the other team constantly fight an uphill battle.
The first issue could be solved with a simple Captains mode format, just with 26 heroes in the pool to ban and pick from before you go into the skill drafting phase.
The second issue can be solved by adding a portion to the draft, before going into the skill drafting phase, where the teams go back and forth choosing the pick order for the opposing team. (Example below)

https://preview.redd.it/viemvkw70n871.png?width=1920&format=png&auto=webp&s=9d462d1e2d0ab402f63b2a3e9d8fe72c324ef031

There is so much about ability draft that lends well to a competitive scene as long as the random elements are addressed. It allows for an unfathomable amount of theory crafting, you have to be extremely good at reading the game and knowing game mechanics, and you have to be skilled at adapting on the fly, because you will never have experience playing against the heroes on the other team.
I realize that it will still never be as balanced as normal game modes, but there is so much that ability draft brings and such a simple way to address the majority of its balance issues that I feel it should get some time in the limelight on a competitive stage.

Side note:
I worried about the total time spent drafting, but after looking at possible numbers I realized it's very doable:
60 seconds at the start to oversee which heroes are in the pool
10 seconds for each ban and pick (less than regular captains mode because it's just the hero model)
10 seconds for each pick order assignment
7 seconds per skill pick (as it already is in AD)
the usual 130 seconds of reserve time per team)

This totals to 15.6 total minutes, which is less than the drafting time for captains mode (17.5 minutes).