I think that The policy on random trainers should go as follows.
-Must have Same number of pokemon
-Must have atleast two pokemon from the reigon you are currently in
-Must have atleast 1/2 of thier team be 1st evolutions for the first 3 towns, 1/2 2nd evolutions for the second 3, and 1/2 3rd evolutions for the last 2 towns
-Must have Same number of pokemon
-Must have atleast two pokemon from the reigon you are currently in
-Must have atleast 1/2 of thier team be 1st evolutions for the first 3 towns, 1/2 2nd evolutions for the second 3, and 1/2 3rd evolutions for the last 2 towns