The Sardinian army in our time frame is a bit difficult to concept given that descriptions of them are vague and most of the archaeological evidence for military features predates our game by a considerable margin. Admittedly in their past the Sardinians had possessed relatively heavy infantry but while I certainly don't claim to be an expert on Sardinia I have not seen evidence to suggest a heavy infantry in EB Sardinia. However, if you were to present a case with evidence of 4th to 1st century BC Sardinian heavy infantry I would try to get it in, no guarantees.

The current Sardinian unit conception is based off of the battles of the Second Punic War and the subsequent difficulties the Romans had with subdueing the island. It was during the Second Punic War that the general Hampsicora, called the leader of the Sardinians by Polybius, made use of cavalry, however the Romans routed both his infantry and cavalry and ran down the Carthaginian allies to boot. By the by, do you happen to have any images of Sardinian horses?