Something really should be adjust with points won/lost, cuz I've won games dominantly but gotten 12pts then lose by 1pt but lose 18pts. The balance of reward/penalty just doesn't seem to make sense. If it is a comparison of ELO vs ELO or Rating vs Rating, then Arena should only put you with similar rated players.
......especially with supposed random dice rolls(total sarcasm)
......especially with supposed random dice rolls(total sarcasm)