BA are way late in closing this so the people who are still in it should not go on strike but be immensely grateful BA have kept this going as long as they have (one of my ex employers shut theirs 20 years ago).All this talk of a strike regarding this would be short sighted; BA do after all have to be around to pay the liabilities.
If you are over 50 in this scheme, with long term interest rates being what they are, you should definitely get a valuation as recent changes in legislation have given much more flexibility with what you can do + the potential ability to pass on pension pots etc. A lot of people in defined benefit schemes also don't realize that if they die before they take their pension then they (the Estate) might only get back contributions paid in rather than the potentially much larger pension pot value.
As stated, take proper professional advice before doing anything with your pension.