Honesty hat on as a 737 BA driver (So Gatwick - But the same issues apply)
Just for understanding purposes, the 1000' 'gate' applies to radio altitude, not aal - Important where it comes to 08R at LGW as Russ Hill moves the goal post.
To see the variation in target speeds on our fleet let me give some examples -A 'heavy' 737-400 has a Vref of 138Kt, so we aim to fly 143Kt. 17Kt loss - No problem. A 'light' 737-500 (look out for the inbound LUX and HME services) have Vrefs down to 108Kt, aiming to fly 113kt - 47 Kt loss which is quite a problem.
On the fleet we have quite a range of experience, the newbies are trained to slow by 5. I do try to encourage people to go further before slowing, but they don't always feel comfortable doing it. Thing is, using common sense you can judge when to slow down to achieve the 1000' radio altitude gate, and most of the time on 26L you can go all the way to 4d. On 08R, you can't do it in a 737-5, 737-3 or even sometimes in a 737-4 due to Russ Hill. But not everyone thinks about the goal - Just the fleet worst case hence they slow down early!
Now this is a BA type problem. There was no problem going back 5 years on the 737, as we had to be stable by 800' Radio but things changed and that backward step prevented us fitting in with ATC. But then we fitted in with BA and that was deemed to be a good thing.
Hope that helps - I do tend to ask for 170/5 coz it does 2 things (we meet the speed that is agreed and we keep the gear up significantly longer) but a few of my colleagues don't seem to see the benefit. Keep the pressure on and I am sure that our management will see fit to come up with a plan that keeps the traffic flowing. You have to sell it though - If they can come up with a plan, just think they might get some extra slots due to greater efficiency. With that carrot, I'm sure they will talk....