I think most of you miss that Grand Arena will be a 3 ROUND EVENT:
1° Round: ''BAD'' PLAYER MATCHED WITH BETTER PLAYER WILL LOSE
2° Round: ''BAD'' PLAYER MAY WILL MATCHED WITH A ''BAD'' PLAYER that lost the previous round
3° Round: IS VERY PROBABLY THINK THAT ''BAD'' PLAYERS WITH 0 WINS WILL BE MATCHED TOGETHER and have a close battle.
So during the entire event even a not competitive player with wider roster but less modded/geared has chance to find at least one time another player with similar roster.
The event is planned fairly, it's a grand ARENA. In normal arena who has better toons/gear/mods/defence/zeta usually wins the best prizes. The same should happen here according to the aim they explained in the announcement : find the best swgoh player.