The problems are quite easy to addres actually, just devs don't seem to look in the right direction ( guess they are too busy launching heroes and greedy events )
1) game desperately need a complete rebalance... Expo and Cryp becoming a chore it's mainly due to the fact that 80% of the time you face the FOTM heroes in a pack.
2) Expo and Crypt should stop taking pt from players. Like lots of other game just randomize the party internally.
3) Items requirements went waaaaaay to far under US management. They trowed promotion after promotion barely rising the lower tiers items droprate. Not much to add ... You don't need a ganius to realize that whales pretty much capped all whorty Herors and are just waiting for the next Tier. Now a good system wiuld gradually lower O+8 and lower requiremens while making C+1 harder..... But guess it's to hard to get