I believe that it would be massively appealing to introduce a personal banlist for Commander open play queues.

When a game is started, the creator may have the option of specifying individual cards, or maybe a deck comprised with the desired cards. Any player attempting to join the game would have their deck checked against the specified banlist. Conflictions would remove the player from the game with a status explaining the issue.

In paper, it is common for a regular play group to sit down, discuss the official Commander banlist, make adjustments, and then players will build decks everyone agrees matches the discussed adjustments.
For paper games without an established play group, it is still very common for everyone sitting down to highlight potential cards of contention or ill repute before the game starts. If players are uncomfortable with specific cards, they may choose not to play or switch to a different deck or cards may be removed & substituted.

In the current Commander Open Play lobby, almost every game created specifies specific cards the host does not wish to play with. However, too many players join with the offending cards anyway. This creates non-games where players just leave immediately and the game dissolves. Some players do this on purpose. It can take a very long time to finally get a good Open Play game where everyone is meeting to specified requirements. In a digital client, with absolute control over everyones decks, this should not be so difficult. Games should be more customizable.

I was playing an opponent and they had Anje Falkenrath as a commander and played library of Leng. They had a creature of which I cannot remember but it had the ability that whenever you discarded a card with madness it got +1-+1 until EOT. So my opponent was using Falkenrath with Leng to discard a card to the top of his labrary and re-draw it using Falkenrath's ability to infinitely pump the creature and swing for lethal trample damage with the pumped creature.

My first thought was that the discarded card he was discarding was not revealed. So how did I know he was actually discarding a card with madness to the top of his library. So I researched Library of Leng Rulings and it noted that the discarded card did not need to be revealed unless another ability states that it needs to be. Which I get but it still didn't make sense because in a paper game how would the opponent know the card being discarded has madness. It made no sense. And then I checked the other rulings for Leng and it notes that a discarded card can only go to the top of the library if it's being discarded to an (ability) otherwise it would go to the yard. Well, my opponent was discarding the "madness card" to the top of their library as a part of a cost to activate Anje's ability which the Leng rulings say that it cannot go to the top of library, only to graveyard because it was discarded as part of a "cost" not an ability.

So there are two bugs I see here with this scenario.

-The madness card was never revealed to prove it had madness to your opponent.

-Second as I read it, Anje and Leng cannot work together when discarding to Anje's activated ability "cost" of tapping and discarding a card to draw a card.

This happened on MTGO and the interaction worked online and I was not shown the card being discarded ever.

I believe this to be a bug.