Yes it isn't all about money, but bear in mind that easyJet LGW does not mean bad lifestyle.
Home most nights.
Car park (potentially) 5-10 minutes from the crew room (good luck doing that in LHR).
More money earlier on in your career (may equal better lifestyle for you and your young family, rather than when you're 65).
If the lifestyle you want is longhaul, then ezy isn't for you, obviously. However I'm not sure shorthaul BA is (at the moment) any better than ezy LGW.
I'm not saying it's all roses, it is hard work, and there are issues to be resolved (ie. sustainable career - which BALPA is working on), but for me personally, I wouldn't make the jump to BA.