To be fair, there is probably less said about tactical deployments than we would like.
The Byzantines were using mixed units and probably advised the Crusaders to do the same. After their first encounters with the Turks they must have seen the benefit of protecting their archers with spearmen. It is only down to 'Roman /Byzantine military manuals' that we get this detail of 'drill and deployments'. Most other written history is of a rather more narrative complexion.
Although little written evidence exists, it probably wasn't Richard who was the first to shield his archers with spearmen; his novelty was how he got them to reload and fire (IMHO).
Given that the Turks, Byzantines and Fatimids all operated in the same region, I find it hard to believe that such mixed unit orientated tactics were not common place. Indeed, perhaps the tactics were so common place that contemporary historians thought such deployment need not be described.
This kind of absence of 'fact' is very common in military history because the historians are working on the principle that common knowledge need not be repeated; they are there to tell you something that you wouldn't know: They tell 'the deeper political story'. This absence of detail stretches well in to the 18th century.
I would ask GWA to state his cases that would prevent such a deployment. If he can, then I will bow to his superior knowledge.
BTW, stating that an army 'deployed its archers up front' would not qualify, as archer units may have had screening spearmen as a matter of course in a cavalry friendly environment.
In short, show me the manual.