I would love see a show tank of maybee 4-5 differenet peacock bass species and a silver or black arowana with them, also a store with more than a 1 day return period on freshwater fish, of course a staff who knows what there doing, clean tanks without dead fish in them, reliable and well kempt enviroment for feeder fish. I also would love to see a place carry good fish food, and of course last but not least... I don't want to see Betta's in lil bowls or cups, put them in 5-10 gallon tanks with 1 male and 3 females or something, just no bowls.
But for advice on the store don't go to crazy with the monster fishes just cus we had a really awesome pet store near my house with a incredible selection of rare and monster fish but they went out of business because there common fish, non aggressive, and pretty much basic fish section was pretty pathetic. most of the average customers it got were looking for inexpensive colorful community fish which it lacked in.