It seems the progress missions order doesn’t make sense.  

Assuming the design is for players to follow steps through development of your champions, why or better yet how can one  obtain the 1200 silver medals required to complete the “great hall” missions prior to reaching silver 2 which is the 2nd to last mission in the chain.

I get the missions should be goals and take a while to achieve but if the order is going to make zero sense, why not allow a player to work through the “tier” of missions in any order?