Also, if you guys are going to keep drawing comparisons between Dota and Hots then it bears pointing out that the archtype mechanics fundamentally operate in completely different ways.
In Dota, a "support" has a kit that is strong enough early game to not be item dependent and a "carry" has a kit that is item dependent early game and thus requires farming. If you look up the Dota roles and read their defining mechanics and match those up with the heroes you'll see what I am talking about when I say that their characteristics fall on one side or the other between being strong early game or late game.
Revamping traits to function similar to items won't fix the issues because our heroes have static roles and everyone starts out equally powerful (except a handful of heroes whose talents can scale over time because of last hits or collecting globes, etc. that kind of function like traditional carries).
Speaking from the perspective of a long time dota player, quest traits look like Blizzard's recognition that their initial use of talent trees can't manifest into an adequate way to control a hero's power curve a la dota items without the game becoming stale. TLV is one way of controlling a hero's power curve through time and Chromie's design does too but in the other direction. Then they experimented with structures and minions to try and control specialists' power curves.
As someone who plays supports frequently, my perspective on what happened when Blizzard gave them a thorough review wasn't that they thought everything was fine but rather they realized they didn't have a good idea of how to fix the problem. That is, they don't have a good sense of how to control a support's power curve other than adding/removing utility and then tuning/detuning their healing. That results in relegating their support heroes into relatively stale roles. A big problem now is that when they started they made healing so fundamental to the game's dynamics it's difficult to unwind its importance.
Anyway, the reason they can't simply have malleable roles via talents isn't because it would break the role or matchup system (because if you think about it, it would actually solve the issue of not having a very good healer or damage dealer in a QM or public game if you could simply talent into the deficient hero-space), but rather because it would throw the entire game's mechanics and balance into chaos.
They were willing to make the scaling changes last year, which fundamentally changed how many heroes played and were balanced. It didn't change any of the core philosophies but it was a pretty radical power shift and balance disturbance.
I think that the problem with healing is just something they realized they can't fix immediately, and doing a "fix" that doesn't change core philosophies about "always being in the action" depends more on things outside of existing healers/supports themselves being changed.
As a general rule, I believe they should focus on giving future supports (and existing supports that go through major updates/reworks) far more utility and damage
prevention mechanisms rather than straight healing because these things are interesting and involve more counterplay.
However in order to make utility and damage prevention more valuable than they are now versus straight healing (so that heroes with these mechanics get picked over heroes with straight healing), they need to add better methods of initiating engagements from a distance so that initiating on objectives is easier, making poke wars less common.
HOTS needs more things like Sundering and Fly + Gust. DOTA comparable heroes like blink+Axe, blink+Tide that powerful initiation/CC combos. Things like Kunkka torrent or echo stomp that have huge cast ranges and can initiate on objectives from afar.
Beyond that, I'd really like to see more heroes like what they did with Medivh and heroes like Beastmaster that provide shitloads of utility for tanks and damage dealers, hard CC and maybe siege but don't directly do lots of raw damage or healing. That Medivh game on Towers of Doom from this past weekend was one of the coolest HOTS games I've watched in a long time. The game would really benefit from more heroes like that.
But overall I think the biggest reason healing is so valuable in this game is the total lack of initiation mechanics. If poking didn't matter as much, sustained healing wouldn't matter as much. DOTA without blink daggers would be a weird place. HOTS right now feels like what that might be like.
