lae, would you have preferred they offered nothing?
While it could be argued that the previous year they could have comp'd you Plat based on the past years we have no way of knowing the exact situation based on what you've written. You then admit you dropped off QF flying for various years, dropping to Gold and then getting <400 SC tthis year. At least an offer was made to extend - and this seems to be the new system rather than comps which fine., is annoying to "lose" an unpublished benefit that previous existed, but this is the new world.
Were you expecting them to just renew you Gold again with nothing? Or is the price in points your quibble? Yes it's fairly high, but some people are points heavy and would see it as worthwhile. Maybe not for you.. it's a value equation for everyone and it will be different.
When the trend of your spend / SC earn has gone down for the past few years how does it look for them? You got under 2/3rds of the way to Gold requal and I'm not quite sure what you were expecting?
I may seem harsh in this response and perhaps I am being... there's got to be a line somewhere though no?