While we're looking at high pressures, supercritical drying doesn't look like a bad idea. It has no phase change, so it might be less damaging than even what you're suggesting. It's not something you could just wake someone up from, but it might work better than normal cryonics. Once they're dried, you don't need the pressure, so it's easier to sustain. And even if the temperature does rise for a short time, the lack of water will probably help preserve them longer.