My experiences are roughly similar, having been in up to 50kts in a Lagoon downwind. However, on a particular Lagoon 570, a faster model, crossing from the Azores to Europe we sailed into 2-3m chop on top of the swell, with winds building near Cabo Sao Vicente. The waves on P quarter, occ. beam-on. Slowed her down from 16+knots to around 10-12kts but still waves hitting the bridgedeck. No one was able to sleep inside...very noisy slamming...So it's not all roses and rainbows....
The cockpit is a bit high up and exposed indeed, it fits the design concept of most Wally's though: Cruisers with racing legs, intended for the Med, not cross-ocean beating in big winds/waves. This one in particular was commissioned with a unique design concept from an leisure point of view: the "terrace by the sea" layout which means there cannot be a cockpit aft.