I like it. I would also add a little mass to the hull, but other than that I have no objections.
Maybe a minor one to the name. "Phalanx" doesn't fit the naming much (but neither does Challenger, so who really cares).
The Bretonia LFs are named after cavalry (Cavalier, Hussar), HFs after knights in general (Crusader, Templar) and transports after horses (Clydesdale, Percheron). An infantry formation is close, but not exactly there. I could live with the name, but it would be wonderful if a better fitting could be found.
Hard to decide if it belongs to the "cavalry" or "knights" line. I would choose cavalry, because it has closer to the Cavalier in design. I didn't find many useful names, I will list the silly ones too:
Dragoon
Cuirassier
Cataphract
Charioteer (could be seen as cavalry)
(shame the Lancer is taken)
