dorosenco
A lot of what you say is not done on JAA is of course taken into the theory exams, which are much harder (we have had students with full FAA ATPLs that have struggled with the JAA course). Not necessarily the best way of doing things, but these are not left out.
Briefing approaches and procedures is not really appropriate for a single-pilot IR (which the JAA one is, specifically). That would, I presume, be tested in the type rating, after being taught in that and the MCC course.
GPS is coming into the IR. It is in the new in the syllabus my employers have developed, though not yet in the test as it is not yet legal for a primary navigation in the UK.
Oh, and "you are not supposed to continue in IMC without an IR" is correct, and this part is being changed to a recovery to the airfield IMC, I believe. However the old system is good - you may have little choice but to divert IMC. Although that would suggest poor planning, that is not unknwn in commercial aviation, I have heard of it in flight instructors!