10W - I quite agree. Though I'm in TC so thankfully don't have the 'nause of having to issue a STAR, it sounds like a perfectly sensible addition for datalink. Some would argue it would increase it's useful applications to one....
However the significant issue was illuded to by 250kts. The problem of a crew saying they are 'expecting a WILLO 4C' is that they haven't actually been issued with a clearance and have not read back a clearance limit, which is obviously a compulsory item. The potential problem is then passed down the line as, given no further clarification, perhaps two-thirds of European crews just hold at the inner hold, most of the remainder would (and do) ask for confirmation whether to hold, and [I]some[I] will make up their own approach and toddle off downwind.
So extending this is not entirely without risk, unless proper procedures are agreed with robust SOPs for each airline.