He can lose 50 HP, but his lifesteal is pathetic and the only that makes his close range actually threatening. To nerf that would be to remove his threatening presence.
He’d need several buffs in order to be okay in 6v6. He came into 5v5 with several nerfs to his damage, spread, and mobility (Wraith form not being able to leave CC).
And by going back to 6v6, I assume you also mean a revert of the season 9 patch.
Just change shadow step to a hold-and-release control and let him move during it.
You can do this in the settings already. I forgot what the thing was called, but it’s something like “activate ability upon release of ability button 2” or something.
A revert to a bad patch, of course 
I think they are still working on it, but haven’t found an answer they like yet.
Actually both. the issue with Wraith form is that it’s his one ability he has to use for multiple key things.
he wants to reload quickly to keep up the dps?
Wraith
he wants to chase someone running away?
Wraith
Wanting to run away yourself?
wraith
want to dodge a deadly move?
wraith
want to cleanse yourself?
wraith
want to stall on the objective?
wraith
now of these may seem like great traits and in a vaccum they are, but since they’re all tied to his only good form of survivability it means he’ll often times have to compromise his own survival in order to achieve one of the aforementioned goals. and so by doing so he is making himself an easy target to kill.
And while yes he has 300hp and lifesteal. his lifesteal is very easy to mitigate and hamper thx to it being a shotgun based healing. and 300 hp isn’t enogh when you have a giant hitbox and are always on top of the enemy.
I would be absolutely dumbfounded if they haven’t dropped it yet. I found the reddit thread of them where they first announced it the other day and it’s over a year old now.
https://www.reddit.com/r/Overwatch/comments/18g8m6p/comment/kd2xzzc/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
Alec said this:
"Reaper is also on that list! Had our first brainstorm and have aligned on our overall goals for what we want to see with Reaper's abilities. One of those goals is modernizing Reaper's kit, Shadow Step and Wraith Form standing out there.
We may also explore some new abilities for Reaper (on the right-click), but don't want to take the space just because it's available. If we add something there, we'll want it to give him slightly more decision making in-combat than he has currently."
And I’m fairly certain that there was an interview even before this where they teased they were working on his rework alongside Cassidy.
Now that I think about it, he was the Sombra rework before the Sombra rework existed.
Not to mention, he’s proportionally weaker than he was pre-season 9 patch in accordance to everyone else (he should be at 333.33 HP with the scaling that they chose for the lower end of the health pools).