In all this debate one needs to distinguish clearly between medical standards to be 'achieved' for the different levels of proposed EU licences and the process(es) by which those standards are evaluated for a given applicant.
The ICAO compliant private pilot licences proposed by EASA will need ICAO compliant medical standards - thus ICAO Class 2, which I understand broadly is less onerous than the current JAR Class 2. The LAPL was developed specifically to meet the requirement from various stakeholders for sub ICAO licences. The sub ICAO element was driven primarily by the need for proportionate medical standards in order not to disenfranchise national licence holders, such as those with the UK NPPL (A) or NPPL (SLMG) who fly aeroplanes that fall within the scope of EASA. Also, of course, gliding and ballooning now fall within the scope of EASA (n.b. for gliders that are within the scope of EASA as opposed to Annex II ones). Forget NPPL (M) for microlights because microlight aircraft are in Annex II and therefore outside the scope of EASA. In the case of UK gliding it has long used the DVLA medical standards (groups 1 and 2) which are the NPPL medical standards and therefore it was vital that an equivalent licence level with associated medical thresholds was available under the EU system. Hence the LAPL (Sailplanes).Otherwise a considerable number of pilots would be disenfranchised on transfer to European licences. The SPL is the ICAO compliant gliding licence, which only differs from the LAPL (S) in respect of the medical standards and process (GP allowed to do LAPL medical but not SPL medical).
My understanding (I would need to look up and check advice from the UK medical 'guru' on this) is that the proposed medical standards for the LAPL are almost the same as the UK NPPL, and are based on the FAA Class 3 (but I stand to be corrected). Therefore, prima facie, the vast majority of NPPL holders should be able to meet the LAPL medical standards, assuming no change in medical condition. But I am not a doctor so don't hold me to that, please.
The key debate has been and still is (even more so with the latest CRD changes from the NPA) the proposed conditions that GPs would have to meet to enable them to issue certificates of fitness to fly (as opposed to the current NPPL bases of endorsing the pilot's declaration of absence of disqualifying conditions). The AME lobby has at this point convinced EASA that a GP would not only have to be qualified as a doctor (fine!) but would have to have, as yet undefined, 'aeromedical knowledge' (or hold or have held a pilot licence of any sort). It does not take much imagination to realise that most GPs will not meet these additional criteria and are unlikely to be motivated to obtain at least the 'aeromedical knowledge' for the small number of patients who require the aviation medical certification for the LAPL. And of course we all know that moving to a different GP (who happens to have the required additional qualifications) is far from easy or desirable.
So we can see that the AMEs are effectively trying to exclude the GP from what the Commission and Parliament intended - a GP route as an alternative to an AME. I wonder why? Answers on a postcard.