Honestly after loot boxes, I feel getting free heroes through promotions will be even more rare. Blizzard doesn't have to give out gold or heroes anymore, they can just give loot boxes.
I was actually pretty surprised that Nexus Challenge 2.0 didn't award any new heroes. They will eventually probably due Nexus Challenge 3.0 and I see it more like 2.0 than the original.
I kinda feel always having mega bundles doesn't solve the problems people think it will solve.
Heroes 2.0 generated a ton of hype because Blizzard advertised the launch (includes mega bundle) has a limited time event. There will be always new players and it's impossible to get everyone all the heroes.
People seem to over exaggerate the impact of mega. Bundles. The reason people like to play Assassins is do the fact they enjoy the style of the role. New players would actually prefer better matchmaking than more heroes.
But most importantly, THERE NEEDS TO BE AN OPTION TO JUST STRAIGHT UP BUY ANY HERO WITH MONEY.
In regards to the actual promotion, I think the marketing decisions probably don't line up with the idea that people should always get free stuff.
I mean, Apple and other companies could make their back to school promotion continue for the entire year but they specifically choose a specific time (during summer/before the semester). The idea behind it is that it "forces" people to take action. If you want it aka (if you want to try Heroes) do it now because we have a limited promotion now (Heroes 2.0 launch).
If something is available always for free, the incentive can be:
Cool, I'll get/download this thing now
Cool, I'll get/download this thing LATER because it's free and always there, I don't need to do this now...
TLDR; Not against this promotion but Reddit is over estimating impact of Mega Bundles has on making the game better. People likely to procrastinate if Blizzard always made Mega Bundles available. I think loot chests significantly decrease chance we'll see free heroes from promotions (just give loot boxes instead).