I think for personal travels I would not spend more than 1.5k for a biz class seat. It's when I travel for biz and I need to go straight to the office, busy schedule, boring dinners, etc, that biz class becomes a must have for me. F in my view adds privacy to the biz class experience, food is still plane food and as per the wines, I have better bubbles in my cellar to quench my daily thirst.
That said, I am afraid it will be hard to go back to kettle class. Lie flat is what makes a world of difference IMO, the rest is just smoke and mirrors that you end up enjoying or not enjoying only if you fly a lot. Good news is that with credit cards, various promos, etc. it is not that hard to bank loads of Avios. So if you only fly once or twice a year and plan properly you could fly mostly in premium cabins.