As for issues with collusion in poker... I don't see a problem... If there are 1000's of players and hundreds of tables, trying to organise predictable collusion opportunities when table allocation is provably random would be impossible.
This is false.
All it takes is 2 players and/or bots at one table colluding to give themselves a massive edge...
Pretending collusion is not a problem is either very naive or very dishonest...
90% of play these days is tourneys anyway which are collusion-resistant...
Why people insist on replicating cash table games in p2p poker is beyond me.