The new gym system seems backwards to me

With the old system, you had to prestige a gym to a higher level if you wanted to assign a pokemon to it, and the time and resources it took to do that justified the coins rewarded. With the new system, your time and resources are instead spent only on taking down enemy gyms, which should then logically be the new way of earning coins. But for some reason it's still based on assigning pokemon, which now takes no effort.

Instead, taking down an enemy gym should now give you ten coins since that's the only battling done in the new system, and it would be a much better reward for the effort it takes. You could still get coins for assigning pokemon, maybe five coins an hour to make it more worthwhile, but the bulk of the coins you earn should come from battling. Maybe you could also get a coin from feeding a pokemon a berry as an alternative reward to stardust or candies. This would let you get coins from any gym, whether or not it's full and whether or not it's an enemy gym. That seems much more balanced to me.