Maybe email it to Gabe as a suggestion since he likes getting emails from random gamers.
gaben@valvesoftware.com
Let me know if you get put in so I can complain about it being an OP character played by scrubs and tryhards, and should be nerves for balance
For a while dota 2 had a pve roguelike game mode that was legitimately pretty fun, though valve keeps doing this thing where they make the fun temporary mode ballbustingly hard which I think kinda kills it for the majority of players
I don't foresee a single player game mode tbh but I think finding ways to tell a personal story across your many matches of a multiplayer pvp game is unexplored territory that valve could break new ground in. Maybe a hub similar to games like Hades, with NPCs who have comments about wins and losses or particular feats you pulled off.
It would be very funny for the tedious repetitive MOBA trash to actually be some sort of a disguise hiding a game I'd actually play.