Mm, I think the hope for instructors was that the JAA changes would create the predicted shortages in instructors by removing the self improver route - the hope being that a shortage could trigger an improvement in pay and conditions for PPL instructors.
When the airline industry nose dived a little last Autumn considerable numbers of newly qualified CPL/IR holders added the £5.5k investment to their debt and gained instructor ratings. Couple this with the fact that many flying schools also felt the effects of the post JAR deadline lull in PPL students, and we have a plethora of instructors.
Furthermore, all the instructors from SFT and Oxford Air Training who lost their jobs recently, not to mention those PPL schools that ceased trading recently (European Flyers etc) put large numbers of experienced instructors onto the market place.
If you're under 35 the £5.5K could be better invested in the CTC scheme, or perhaps save your money and pay your debts off with a normal job whilst waiting for things to improve (you're hardly likely to be in a position to begin paying debts off and provide a living for yourself if working as an instructor!)
Whatever - good luck
Ivan