The cultures at this time were even more split up than just German or Celtic, it was normans, franks, southern franks, swabians, saxons, lombards, hungarians, moravians, scots, welsh, irish, flems, rus, etc...

Only in the later medieval period when central governments gained power at the expense of the counts did national identies arise and take importance over tribal identies.

The Crusades actually were more helpful than hurtful for western Europe. For one it gave the younger brothers a place to fight for land outside of his families area. The renewed trade with the Middle East made Europe richer and allowed some Kings to consolidate power (France, Spain) while others became more divided (HRE).