From my point of view, Feeder Fix timings works well, combined with controlled taxi times/COBT. Plenty of aeroplanes inbound but it all works out pretty well, with not much holding. We generally do get more warning than 15 minutes though.
Quite frankly, where I operate, balls to the ball to the 36nm fix and then hold would be childish. Might need it at LHR, not here.
I'll say it again, for those complaining about having to slow down when high, have a look at your best holding altitudes. Get down, get slow and save fuel...