Have they ever done Finsbury Park to Moorgate in the peak?!
Bar the one or two 3-car services, once a train leaves Finsbury Park to Moorgate it's not
too bad. Can't remember a time when I couldn't get on a 6-car train after changing there from a faster train from Hatfield.
(And, yes, I could just get on Hatfield when it would be mostly empty - but I hate loads of stops).
A lot of people get off at Finsbury Park, and even more at Highbury & Islington for the easy interchange (although now I'd argue that with the new stairs, it's better to change at FPK all the time unless you need level access).
Coming back though, Moorgate services out can be rammed by Old Street and stay that way until a few stops beyond FPK where the train gradually gets emptier and emptier, with few people getting on. Until the new trains come, with open gangways and wider aisles (I assume) with none of the wasted space from the middle cabs and storage areas, I can't see that changing. However, there's a pretty good service frequency so missing one train isn't that big a deal.
I think FCC (GN) managed to get a lot of services off the top ten with the strengthening of services by obtaining more trains, fiddling about with the timetables etc - and of course Network Rail doing various upgrades. One thing FCC and NR, and perhaps the DfT (don't know) achieved that made a big difference during the last franchise.
That does surprise me, the Heathrow Trains always look to be almost empty!
Heathrow Connect can be VERY busy. I know as I've been on them quite a few times in the evening when they're basically commuter trains that happen to go beyond Hayes & Harlington to Heathrow. The train can be packed, so you need to board as soon as the train gets in to Paddington (especially with any bags) and by the time it gets to Heathrow you'll be one of the only people on it, plus perhaps the odd member of airport staff (after all, most people aren't 'Smart Londoners' to quote their advertising and pay the extra for HEX).