Going back to the original point on trains/buses - I agree about the overcrowding on Overground completely, and the interchange at Canada Water is insane (one down escalator, no stairs...who signed that off!?).
My experience (20 years plus) is that trains are much more reliable than they were thanks to investment over the past couple of decades - really they are. However in that time there has been so much building around our areas, the working population has significantly increased. Just look at the flats built around FH in past 5-10 years. It's brought a welcome boost to local shops and eateries, but train sizes haven't kept pace. A solution would be for Overground to run 10 carriage trains but poor old north London can't cater for them (couldn't resist a dig) so we're stuck with 5. I suspect that investment costs to change that would be prohibitive. The London Bridge revamp has caused disruption, hopefully we're coming to the end of that.
On the positive side and a journey that can be more pleasant - I just checked out the proposed changes to London Bridge timetables from 20 May (here) and overall, cuts I feared don't seem to have happened, though on a quick check towards London Bridge there seem to be 4 trains 7-8am, and 6 trains 8-9am. If you pick the right train/location you can normally get a seat, and you can change for very frequent services to Waterloo East and Charing Cross - if there are onwards options that would suit you from there.