Top teams with trophies are going to always have an advantage. This point is moot.
Here is the thing about a herocon such as this.
Training takes time. If you don't come on and do the time to train your points (not talking donuts here, just training) you won't get the points. Some people don't have multitasking thus, they don't train like they should. So for every point those trophies give, unless someone has paid/saved to get multitasking, how much do you think they are actually going to train?
This type of herocon I think would require participation more than more than most.
Its easy to come in and quickly sell items. Easy to come in and fight a few rounds. Easy to come in and just buy skill points and run back out. But to train? You got to be here or return often. Again not talking people that stack and use donuts with skill points, talking the average, not paying player.
I still think a few herocons should go the way of the dinosaur (cough special missions cough) .. and new ones, like this be implemented.