Curved swords didn't really kick in in the Islamic world during Crusades.
You've got to define "better" I guess.@awa: Armour and metallurgy usually get better as time goes on. The exception is when people started to find armour unnecessary and started decreasing it.
It certainly got way better since around ~ 1400 but that's somehow 'fresh' and unique process.
Before, metallurgy was at somehow similar level in Iron Age, with a lot of regional and periodical differences, original achievements, innovations etc.