Int32x4   rot

Int32x4 rotary shifts: Ubiquitous in crypto. Big performance gain on ISAs with vector rotary shift (e.g., XOP instruction). Easy to desugar to shift, shift, xor on platforms without.

Float32x4,64x4 FMAs: IEEE-754 FMAs are evaluated with infinite precision and then rounded. This provides  for some applications, high numerical accuracy improvements; can make the difference between float32x4 and float64x2. But need to know whether platform supports IEEE-754 FMAs (all ARM with VFP, very recent x64).

If these proposals are interesting, will contribute some sample code.