More Hero Proficiency Rewards

[Terotrous]

The Hero Proficiency system is a great feature (fun fact, Overwatch had something similar in its Alpha, but it was removed in favour of lootboxes), but it could use a bit more to unlock. I'm already almost at the second-highest rank and I've seen a fair number of people at the max rank with the game only being a bit over a month old, ideally we'd want there to still be stuff for people to unlock for years to come.

I feel like they should probably add about 4-5 more ranks past what's already there, with each one getting progressively longer to unlock (as it is now). Perhaps at the last rank, it would just continue going up forever but just add a number to your rank.

Some ideas for stuff they could give you for the higher ranks:
- A title (there's currently very few titles in the game)
- A hero banner
- A skin (it's probably fine if it's just a recolour of the base outfit)
- A profile mark (you can currently only earn these from ranked play)
- Maybe a third hero avatar as the final unlock

I also think it might be a good idea if the Hero proficiency challenges also rewarded a small amount of the purple currency. This gives players a way to continue to earn purple after running out of daily missions to complete.