For me it is a yes.
In the last month in Britain I have visited and/or played Reigate Heath, Royal Wimbledon, Ballybunion, Lahinch,Worplesdon, Sunningdale, La Moye and Royal Jersey, Porthcawl, Southerndown, Alwoodley and finally Slaley Hall.
At Slaley Hall by friend Bill Longmuir bought a copy of the Confidential Guide for a Spanish player,Domingo Hospital to see. Domingo is a huge fan of Simpson because of his influence on the continent and one of very few on the tour to have any interest in design.
The book was passed around the players room at lunch one day - amongst the Irish especially - and none had ever heard of it which was suprising to me in one sense but not in another.
It is always intersting to see old courses for the first time or to revisit ones you have seen many times. It reinforces why great is great,good is good and poor is poor.
Slaley Hall is a 'new' course (maybe 15 years old) and it forces you to ask why the principles that made for the brilliant old courses (I would include all of the courses above in that group even though some are clearly better than others) over here were just disregerded completely.
It does, however, qualify as a Ryder Cup course because the 9th hole comes back to the clubhouse!