What I wanted to emphasize is that the rules generally make a good point by effectively disallowing something like to actually work under standard adventure play; however, the phalanx was very well known for the use of two weapons primarily: any pike (from the Roman pilum to the Macedonian sarissa) and any "short sword" (from the Roman gladius to the Greek xiphos) for close combat, should the pikes prove problematic. For all it's worth, creating a special upgrade (proper training was still needed) that allows a pike formation to bear shields for an extra cost (i.e. an increase in its defence) does not seem that problematic to me...