Correct. It was actually Ana, Sojourn and Sombra.
This is largely false.
New heroes coming into the game - particularly those from the Damage-role - never did reach peak numbers of the original launch roster. And two of them, had some serious issues with being successful. Sombra was marred with a rather poor and heavily restricted kit, and Doomfist’s designed was flawed from the get-go and had numerous bugs and issues with landing successful abilities and attacks. The latter two, Ashe and Echo were much more successful, especially after a recovery tweak to Ashe’s gunplay that necessitated a downward tweak to her damage.
Supports did have problems, but these were largely numbers issues. Every Support post-Ana, was healing more than the last, especially Moira and Brigitte. Moira was blowing so far past all other healing numbers, and there were several tweaks to other Supports (like Lucio and Mercy) whose healing got even strong, if more limited by range and the removal or change of an ultimate. This inevitably led to the double-Sniper and Grav Dragon metagame, and Brigitte just flew further past that and became the catalyst for GOATS. 20 healing per second for 5 seconds from Inspire and 150 healing from Repairpacks that would lead to 75 armor overheal. Not to mention her stun combos could kill Tracer in less than two seconds.
Tanks were the larger issue, though. Starting with Orisa introducing the Fortify mechanic that would later be passed onto Roadhog and later added to Reinhardt in the form of Steadfast and Bastion in the form of Ironclad. Wrecking Ball became the fastest hero in the game (previously reserved for Lucio), and Sigma re-introduced the Double Barrier metagame for 2/2/2.
However, most of the heroes didn’t introduce new mechanics, only Ana, Sombra and Orisa did. TTK skyrocketed as new Support healing was introduced and buffed, and every new Tank had some crowd control to control teams. It was pretty evident that Tanks and Supports were causing issues, but mostly in terms of numbers, rather than in specific mechanics.
Reaper, not Genji.
Only in beta, D.va was added into the game well before the final two beta tests.
Sticky Bombs and Duplicate was a concept introduced before Overwatch launched. Blizzard had always wanted a Railgun hero, too. Sticky Bombs would eventually be part of Echo’s kit, but it also appeared as Tracer’s Pulse Bomb.
Orisa had a smaller kit than Reinhardt.
She did. Several times, in fact.
Genji wasn’t performing after GOATS. He was seen as mildly overpowering in beta, but after they dropped his damage from 32 to 28, he appeared to be performing just fine. They had considered giving him 150 health, instead, but the damage reduction seemed to be enough.
Apparently this had to do with where they wanted her, they didn’t initially consider her a Support hero, but they did Sombra.
Yep, they even hinted at her at the end of beta when they announced that going forward all Supports would be healers. And her map; most people thought she was Sombra.
This was notably around the time they reduced the duration of Dragonblade.
There are some serious rose-colored glasses here about 6v6. First, we didn’t get 2/2/2 compositions until the end of OW1, and it only last a year and a half, shorter than the GOATS meta.
Second, it was demonstrably clear that Tanks and their synergy was a serious problem to the point that much of the Damage-role was rendered largely irrelevant. If anyone did creep out ahead of time (such as Mei) as a counter to their, they were tweaked to become less of an issue. The catering towards Tank metagames and compositions was a serious problem, and the only way they could solve it was to introduce 5v5.
Or they stop using the templates they’ve been using since day one of OW1’s alpha.