One small feature that I never thought I'd miss as much as I do is the dissolve blend mode.  Surely adding it shouldn't be too difficult, and it's such a great, easy, and effective way of adding texture to your work. Kept an eye out for it in the latest Beta, but unfortunately it has been added.  I'm almost feeling a bit crippled without it - please please please consider it for the official Affinity Designer update!  I would be eternally grateful.