Watch more Strategus battles. I'm not taking anything away from Occitan here- what they're doing is great, but it's hardly unique. ATS, NH, Fallen+HRE, Mercs, BashiBazouks... there are a lot of folks out there that keep it really, really tight on the battlefield.
Here's the odd thing about it (and why I picked those clans):
ATS was great at cRPG, but struggled in Strat
NH does some of the best looking formations I've seen but has never been astoundingly successful in Strat or cRPG
Fallen+HRE and BashiBazouks do great work in Strat, but aren't exactly dominating cRPG
Mercs are always very, very good at both Strat and cRPG, but don't tend to have the prettiest formations like you see in the pictures above (and Mercs are far, far superior special-purpose forces, nigh the best).
So don't confuse beauty for utility, and sometimes it's even a detrimental.
Plus, tactically speaking, their maneuver with high-held shields below an archer position is not a wise tactical choice. Shield walls are useful in limited circumstances- it's become a joke amongst the NA Fallen Archer Death Squad: "Oh no, hold your fire, they've made a shieldwall!" Siege Shields would have been much, much better in that environment, attacking from that angle against that opponent.