Well done on the beta version! There's already a few features that made me realize that you've got potential to seriously upset Adobe :)
For me, that's the Frequency Separation filter, warp tool (Photoshop: limited to a grid of 3x3) and the blending mode live view.
Adobe has long been neglecting people who used to be Photoshop's core user base: retouchers. I'm part of that user base, and I'm watching eagerly & closely. Here's some more suggestions
-Per-point feathering (already has a thread here) is a good start for even more features.
-Various colour adjustment tools with a user-configurable colour range AND full CMYK, RGB, HSB support
-Vector/Bezier-based color-adjustment and dodge-and-burn tools (similar to your Warp tool, i.e. start with a square (or circle), and add points), ideally combined with per-point feathering
The more "pro features" you put into Affinity Photo, the more Adobe will start to worry.
Keep up the good work!