The PTR has been updated and the community has given their thoughts.  While it’s accepted that Lucio has received buffs, some pro players felt the skill ceiling has been lowered.  Custa, for example, was not impressed:

xQc gives a demo on how Lucio’s new wallride works on circular pillars.

Overall, the changes appear to be welcome to the community as a whole, as /r/LucioRollouts have already found an efficient path on the new map, Rialto:

Another important buff is that Lucio’s Soundwave ability no longer consumes ammo.  This dramatically improves his duels, such as versus Soldier: 76 where you’ll need all your ammo to burst him down after booping him out of his biotic field.

Hanzo’s new abilities

Hanzo is losing Scatter Arrow, but he’ll still be effective at killing Tracer as a single Storm Bow headshot will 1-shot her at 160 damage.

The total damage of six Storm Bow arrow shots deal 480 damage, which appears to open new tank busting opportunities:

As for his new Lunge ability, slanted surfaces such as as rooftops can be exploited to push his mobility options even further.

Possible changes to Horizon Lunar Colony

/u/Eleanthas discovered new changes to Horizon when using a preset with health packs off.  The presets no longer work, but not before they created a video to document the possible upcoming changes.

Much has changed with the latter half of the map.  The upper platforms have changed and the defender’s spawn point is further back.

Unit Lost goes more in-depth and also notes changes on the first half of the map:

Other changes

Minor nerfs have been given to Brigitte’s shield bash, Junkrat’s grenade projectile size and ultimate tire movement speed, Tracer’s pulse bomb damage, and Genji’s hitbox size for his Deflect.

For Genji, /r/itsjieyang provides a visual comparison:

Developer comments are provided for all the changes and appear to be direct responses to comments and concerns from the community.