Bigears - a very good point that seems regularly missed when dealing with IFPS. IFPS only ever applies those routing requirements, restrictions and availability that are supplied by the member states; IFPS never puts in something like that which has not been requested by a state, so the quality received in ACCs is pretty much a direct reflection of what has been given by that ACC to IFPS. OK, there are instances where IFPS gets things wrong, but that's often in data processing, and not infrequently. However, in most cases, IFPS is doing what it has been told to do, and that's one of the main reasons why you get so many routes that pass automatically, but are unacceptable for the ACC.
I'm not trying to start a witch-hunt here, but I think it's worth highlighting the issue to raise awareness of it. Fortunately or unfortunately, according to your perspective, IFPS is a focal point of IFR/GAT flight data in Europe, and that automatically makes it the bad guy whenever something is seen as unacceptable, whatever that may be, and often regardless of logic. This then has a tendency to divert attention from where the real problem lies, as IFPS is automatically considered at fault.
For everybody interacting with IFPS at any level, you might be interested to know that there is a new IFPS User manual planned for publication around the end of March which will provide a great deal more information on how IFPS works. It combines the internal operations manual with the current external users manual, so there is going to be a great deal more transparency in what happens. The text given by Routechecker in his first post here is a copy of a part of the draft version. This new manual may not be to everybody's liking, as it states pretty clearly the responsibilities are of external users of the system, and that will most definitely mean considerably more work for some users who currently tend to make 'optimum use' of IFPS, as they will have to start taking more responsibility for their actions. If you're interested, it's all part of the EU's Single European Sky project, where the Initial Flight Plan concept requires everybody to have clearly defined roles and responsibilities.
Hope this all makes some sort of sense, but I'm rattling this off in a bit of a hurry, so apologies if it loses sense at all.