That's not correct, BA have started more FPP courses than they initially pledged.
I'm not so sure. The FPP have, as someone stated in this thread, a very long lead in time and enter the line with no experience of aircraft operations from previous employment or schooling. This can cause an 'experience' sink on the line which is generally countered by introducing DEP's into the training programme as well.
What this does is 'off load' the skippers at Gatwick by giving a skill variety in the RHS and not foisting keen but inexperienced FO's on every sector.
From what I can gather the business case for a further influx of DEP's is being made at the moment and the advantages of multi age/skill levels are being used as a business plan driver.
The other disadvantage for the FPP programme is future pay/retirement. Employ 800 people on the same contract at the same time will give you a headache if they either all retire at the same time or all remain within the company to PP34!
I expect DEP to be announced sometime this year, only IMHO of course.