Personally I've got very few complaints about the browser, especially after the last update which fixed the link offset issue and improved rendering speed immensely. Cut&Paste outside of text areas is about the only complaint and that's coming.
So given the choice of a browser that already works well or SDxc cards that aren't supported well, I'll take the latter rather than having to reformat to FAT32 with it's limitations.
Really? why? It's not costing them anything extra and they were happy to pay H.264 licencing, JPEG, MPEG and who knows what licencing already. I can't imagine even the most ardent of open source advocate NOT buying something because it supports ExFAT.
Am I repeating myself? The standard says ExFAT, therefore it's 100% absolutely necessary if you want to claim SDxc card support.