I'm so sorry to hear of all your losses :(
My thoughts just based on my own experiences so it's mostly a bit anecdotal:
Train every member of staff in the hospital that might come in contact with somebody having a loss that "It's for the best". I had this after my chemical a few weeks ago from the lady taking my final beta. Was unamused.
Also to have a separate waiting area for people with losses or potential losses than for those having routine scans. I had a post-D&C infection and needed to be scanned. Spent over an hour waiting in amongst women jumping for joy at finding out the sex.
And definitely some sort of acknowledgement over the loss as a previous poster has said. A certificate and potentially a scan photo could really help with closure.
And a bit more diligence with previous notes. For instance, having a scan at 5 weeks and another at 8 weeks and only a week's growth is shown, does not mean "viable pregnancy" and discharged from the EPU. I tried to argue the point with the nurse practitioner but she insisted my dates must be wrong despite the evidence of my notes. Had to go private to get my D&C as they discharged me. Off their rocker.
I'm also pretty sure my incompetent cervix was caused by a forced dilation without a pessary or anything for my D&Cs. My cervix felt in agony afterwards and I was sure something was damaged. I nearly lost DD2 as a result. I've heard so many people have a pessary beforehand and I have no idea why I never did for either of my two D&Cs or my hysteroscopy.
Having the staff actually read some of the Miscarriage Association's leaflets and actually follow the guidelines. They are the experts.
Having said all that, some staff have been really lovely over the years and if they were all like that, perhaps additional pain wouldn't be caused.