Afaik the bottleneck is at the server, but it is not the bandwidth. The problem seems to be that the servers takes too long to process uploaded jobs. At http://tah.openstreetmap.org/Upload/go_nogo.php you can see the queue length, whis is the number of uploads that are not yet processed by the server but already transfered.

What is the advantage of having a gpx track database import completed when one can already use it beforehand? And why are the tracks of Romania not useful?

It's a bug in Potlatch: http://forum.openstreetmap.org/viewtopic.php?id=570
It will be fixed in 0.8b according to a post in the thread.

On the osm main map, you can click on the plus sign on the right hand side to switch to osmarender, which is afaik the same map informationfreeway displays.