The 16 bit index buffer limit is only for some mobile devices (ES2 allows 32 bit index buffers but does not require it, and many Android GPUs don’t support them), but I don’t know 100% about the repartitioning. I’ll ask someone to confirm. Honestly, it should be extremely rare to want to draw a single mesh/material combo with more than 64k verts on mobile…
Cheers,
Michael Noland