This Experimental mode is essentially a follow-up patch to the bigger balance updates, where they want to do a series of small tweaks to the previous balance changes.
These changes are made based on the players' feedback and Blizzard's internal data, and the idea is for them to be in the game for around seven days before they decide if they will stay or not.
With this update, Blizzard wants to give Genji’s Shuriken some more power, because they are worried that Genji, in his current state, relies too much on his Dragonblade ultimate.
Mei is getting a much-needed buff to her Cryo-Freeze healing, while Reaper's Hellfire Shotguns are getting a slight damage boost.
Blizzard thinks that Sigma's previous cooldown increase for Experimental Barrier was too harsh, so they are now slightly reducing the cooldown while increasing Pharah's Hover Jets regeneration rate.
Finally, the patch increases Zarya's Energy drain rate by a bit.
Keep in mind that all these changes are experimental and Blizzard will only after testing them decide if they will permanently implement changes or not.
Overwatch March 4 update full patch notes
- Recovery lowered from 0.75 to 0.68
- Ultimate cost increased by 15%
- Healing-per-second increased from 37.5 to 50
- Hover Jets regeneration rate increased from 35 to 43
- Damage per projectile increased from 5.5 to 6
- Cooldown reduced from 2.5 to 2.0 seconds
- The energy drain rate increased from 1.6 to 1.8 per second