To be clear, I love Grand Arena. It's fun, it's strategic, and it gives me a use for more of my roster than the 4-5 teams I otherwise use for everything. Thanks for introducing it!
That said, it sucks when my opponent places no defenses. If they want to skip playing and just collect last place prizes, that's cool, but I lose out on the opportunity to test out my squads and, more importantly, collect the 100k credits for beating each of their teams.
I know there was mention of introducing an auto-defense-placement feature if someone doesn't put any down, this is just to say that once that's introduced I feel Grand Arena will be truly awesome.