What are the numbers for the armour and size of the Centaur and Ostwind?
I can't find an up-to-date source for stats theses days
you can find them in cruzz's calculator maybe in firesparks file also.
ostwind
Target size: 22 Sight: 35 Speed: 6.3 Accel: 2.1 Rotate: 32 Armor: 110/55 Health: 640
Centaur
Target size: 18 Sight: 35 Speed: 5.2 Accel: 1.8 Rotate: 28 Armor: 160/80 Health: 640
The combination of "medium armor" and small size and lots of AI make very few unit good in countering the Centaur.