The beauty of BA is it gives you a choice: Lifestyle or money. I have watched people 800 places junior to me get their SH command this year, I even flew with a few of them before I moved over to long haul. They made a choice to bid for command, presumably knowing that 2016 was a "one off year". They will now probably spend at least the next 5 years and quite possibly longer getting blind lines, working every weekend and most likely doing the unpleasant stuff which filters through to the bottom. I pretty much think they are crazy for doing it but everyone has their own personal calculation to make and fair play to them for passing the course and grabbing the command with both hands.
To be clear, I'm not suggesting this is you (for starters I still don't fully understand the intricacies of the BMI agreements) but it does illustrate that they made a choice that the money was more important than lifestyle. Personally (LH notwithstanding), I think I'd rather have stayed in the right hand seat of the 320, accepted I was going to earn less but would get every single weekend off, never do reserve etc etc.
Having worked at easyJet I think you'd be nuts to go there. As others have pointed out, you will end up at LGW working ridiculously hard and the roster stability is just horrible. BA are a much better employer in my opinion, difficult though that may be to accept having not seen both sides of it.
Go part time. Leave the 320 and go RHS LH and you will move up. Just don't to go EZY.
Good luck.