If the Pilum stuck onto your shield, you would almost certainly die very quickly in a close combat scrum, especially as most of the people with their shields destroyed would have been in the first couple ranks.
I know that Pila are effective against armored units from the rear, but they should be from the front, also. Plus, against a humble unit of lugoae, a Pila volley will kill 10 guys if you are lucky, while regular javelins from gaeroas will kill many more. All the mentioned effects of the Pilum would have caused many initial casualties, as well as weakening the enemy in the melée.

@gamerdude-I may post a mini mod with this and some other stuff.