Rainboe,
as you probably know, current GNSS (be it NAVSTAR or GLONASS) are not primary aeronautical navigation systems, as the simply cannot be because they don't meet ICAO requirements. The main reasons are quite simple -
1.) No failure warning (receiver has no idea about SVs degradation of any transmitted data)
2.) Not enough precision (specifically in vertical axis - altitude)
3.) No guarantee of derived position
As you can probably imagine, this is a no-go for aviation. That's why there are no GPS let downs authorised (well, not without other systems like baro altimeter or with quite a high minima) and why FMC automatically disregards GNSS position information in favor of IRS + ground external systems.
Even though it can be greatly enhanced using differential methods (mainly ground based LAAS), there will still be the primary problem - no guarantee. This is very serious issue.
NAVSTAR and GLONASS were not even originally meant for civil use and are not run and maintained by civil organizations. I'm not talking about intentional degradation rumors, which were neven proven true (I was actually doing GPS field survey during Iraq war in Gulf area without any problems, so I probably know what I am talking about) or the fear of shutdown of service. I am talking about legal obligations, reliability, guaranteed parameters and service availability. In other words...about safety.
Galileo was build from ground up to meet ICAO requirements a provide required level of monitoring and backup. It's designed to overcome the above mentioned problems. It has the potential (with LAAS) to provide CAT III capability. The extras added which you were talking about are very useful bonus, but not the main purpose of the system. There are many more advantages (two useable frequencies significantly reducing propagation errors being one of the most important, or the more reasonable constellation) which make this system more unique for it's purpose.
No, I'm not a big fan of EU byrocracy. Projects within EU are in many cases useless and very cost ineffective. But nevertheless, it doesn't make Galileo one of them. Project management wise - possibly. Technologically - hell no.