Interesting subject needs new thread.

It strikes me that a glider designed to soar in weak thermals is well
off its design point when running fast in a wave XC or, for that
matter, in strong thermal conditions. Ballast helps, of course, but
the basic airframe aerodynamics are wrong for extreme conditions.
Flutter shouldn't be allowed to become the limiting condition.

There were hints that Klaus Ohlman's Nimbus 4DM was modified to
increase Va and Vne for the record flights. It was never made clear
just what those mods were. With today's records being set in
extremely strong conditions, an increase in Va and/or Vne seems like
it would be more important than any increase in the already high L/D
max.