Sums it up very well. Given up on asking the questions “why?”

I believe some of it has to do with having booked work in a link. (harmonisation agreement). Whereas HSS can do refresh and diverts. GWR drivers don’t have ‘diverts’ or ‘refresh’. The negotiation table for getting new booked work/retaining is like Hunger Games amongst other depots when they meet with route planning.
Most drivers at Padd don’t live in London. Most are in the Home Counties. If they do, bizarrely someone who commutes from Reading can get into work quicker than someone from South London.
We get parking at Padd. (Whilst limited, never had a problem)
If you decide to move west of London, you can have an additional parking pass at another GWR station. Slough for instance.
We don’t have a taxi agreement anymore.
For the trains you get a residential pass for GWR and can get 75% off national rail season tickets with RSTL travel. (Which you also get at your current TOC)
A few drivers live in your part of the woods, some a tad bit further and mange to get in with no problem.
If you do come over, in the lower links it’s MUCH easier to get a swap with someone for perm early shifts in exchange for late/nights. Failing that, many are happy to swap start times. Moving through the ranks from link 2 to link 1 is pretty quick as drivers don’t want to lose their swaps/change rest day patterns. As mentioned our highest link is called dynamic. Won’t be any progressions into it for the foreseeable future.
Work pattern is 4 day week. Whilst Padd drivers (those pre harmonisation) can ‘chuck’ Sundays in, those on newer GWR driver contracts (which you’ll be on) have to work Sundays. You can still chance it by chucking a Sunday in and getting it off, but personally wouldn’t bank on it. This is something that is in discussions to implement a 7 day week for everyone.
Don’t get London weighting (only HSS Padd) or any depot location subs/allowances.
Not possible to transfer to HSS (purely long distance work) as that is ring fenced after harmonisation.
However 800 is core traction and someone has posted the routes you’ll do in link 2.
You’re allowed 1 PTR move. If in the future you want to move to the south west and retire along the coast you can put a transfer in.
Start/finish times can change every link/diagram update. But vaguely said and prepare for 02:45 could be your earliest and latest 01:45. Nights being 19:30 or 22:00 till 05:00 or 06:30. I say these times with a pinch of salt so you can work out whether or not you can get in for those times. Many drive in when they’re in that range. Use night buses or the night time Reading-Padd stopper.
It’s a great depot, with great work which will only increase over time as HSS gets smaller.