I wouldn't say it's virtually identical at all. It's clearly inspired by it but definitely not a case of infringement.
Anyway, this has been a bit of a sleeper hit for me. I certainly wouldn't say it's for everyone and there are some obvious flaws that have been pointed out that I agree with. However, I have no regrets about picking this up - I love Pachinko and knew going into it that interaction would be limited. The use of RPG before Pachinko does lead to some misdirection that it would be the prominent genre though.
I would dearly love to see this expanded on. As others have said, different heroes with stats and equipment to gain that granted special skills. Maybe some NPCs you could collide with that would offer quests like killing a certain monster. I just have visions of a Peggle-style Heroes of Loot; having your hero bounce down winding labyrinths, seeing chests on alternate paths beyond your reach. Beyond visuals, it doesn't feel too much like an RPG.
A ranking system could be potentially easy to implement. Much like Endless Runners use where you earn stars towards a rank up by completing tasks like "Kill 50 monsters" or "Finish 5 runs". You could also keep the gold you accumulate and use it in an in-game shop to purchase costumes/heroes and new areas/themes. Anything to make it a little more substantial. Hopefully I don't sound insulting, I actually love the game, I just think it needs a few touches to appeal to the mass market. Pachinko is incredibly niche and even with the cheap entry price I don't know how many people will risk it.