Font Awesome Free isn't going anywhere. Re-design is largely due to changing the base size to 16px which requires a re-design to keep pixel-perfection.
Thanks. Remaking all of FA Free sounds like a lot of work for little benefit, but I imagine it makes sense in the light of all the extra icons you're adding to Pro.
Honestly, the grid system in 4 is quite inconsistent, especially with vertical centering. But that happens over time with an open source project. Things wander each commit.
Been jonesing to start over for a while. Super excited.
