I must say I'm disappointed by that decision. The 3D option was very well hidden so it isn't surprising it wasn't well used. (edit: and it wasn't available on mobile)
For properly understanding weather patterns a 3D view is way better than a flat projection that doesn't even let you see the poles. I would have thought it was a better idea to stop work on the flat projection and work on a proper 3D view instead which could then be the only view - obviously when zoomed in close it would be effectively 2D anyway.
The current 2D projection is pretty horrible if you live in higher or lower latitudes (even for me living in the UK it gets quite confusing looking at low pressure systems passing to my north) or if you want to see arctic weather and so on (in fact it is impossible to use in that case). Windy has massive potential - if it had a working 3D view it would be easily the best and most accessible resource for so much information about our weather. As it is, it's good but has to be used alongside something like Earth Nullschool to see what is actually going on on a global scale.
Of course I would like to than you all for your hard work in providing this valuable resource for free and you may obviously develop it in whatever direction you like! So thank you very much and I hope you will change your minds later on. After all, the world isn't going to become flat any time soon :)