Oh GOD, I could hardly get through Ashley's description of the nightmare set up!
I still get abnormal heartbeats when I think of the time I brought in a stray to a little clinic out in the exburbs and it was this tiny box "house" with two loose clinic cats and about 8 chairs packed into a square space the size of a whirlpool. I about died, even though the stray was fine. With MP, I often resorted to asking them to come get me when the coast is clear. I felt like a total PIA but every clinic was super accommodating, and it got easier and easier for me to ask. To avoid the reception/cashier area nightmares, I either paid in the room, or a tech or assistant would hang out in the room w/MP while I went and paid.
Divided waiting rooms would be awesome and straight-to-outside rooms would be super ideal! I know of one clinic I did some work for that had a "quiet exit" room for difficult appointments like euthanasia. I thought that was a lovely thought, and would be great for reactive dogs, too. If we can dream, I think pets would like quieter latch doors (not sure if it's a thing, but I just mean ones that aren't so dang loud with "CLICKS" and "SLAMS!") and noise proofed rooms, too. I used to leave the door ever so slightly unlatched while we waited for staff/drs, so that I can reduce any amount of stress where I can, and the staff would make a big effort to come in/out super chill and quiet.