The impression I've formed is that nothing short of an overwhelming metagame shift (ie Dark Seer becoming a staple competitively) or a "meme" shift (ie Singsing Shadowblade-Daedalus Kunkka inspiring copycats) is enough to shake your average pub player into expanding beyond their personal comfort zone, at least as balance changes go. This becomes less and less true the higher you climb in MM, the same is true the more slots you've filled with players you have a history with, but solo queue will always be plagued by this to some extent.
If Dota is to remain a peerless competitive game, Valve needs to continue balancing from the top down, because it is the top that will push every single skill, item, and hero to its utmost limits. The game's middle and bottom can't do that, they exist in a state of pseudobalance, where skills, items, and heroes are bottlenecked by player inexperience and lack of team cohesion. You can build up the players with tutorials, skill and play guides, as well as feedback mechanisms hooked into the game (without interfering with it), but balancing from the middle or bottom is a recipe for catastrophe, for several reasons:
- Such changes will tend to be felt the hardest at the topmost levels of play, and not on the levels you target.
- Such changes may not even be felt at all if you're prudent and careful. If you go overboard to ensure it, you destroy competitive play.
- Looking at the middle and bottom levels confounds your ability to even diagnose balance problems accurately in the first place, because it again comes down to immense comfort zones and whim.
There's certainly means to broaden comfort zones, but what won't work here is doing as League did and taking a hammer to the design, and bringing the ceiling down for everyone.