Continuing the Roman theme, these guys are my scorpion unit for my Imperial Roman army
In the game they are pretty rubbish! The ability to ignore armour saves is useful against 5+ save units, but there aren't a lot of them around. Typically as well people will only line up their troops two deep, so the best their ability to penetrate ranks gives you is 4 shots (2 on the front rank and 2 penetrating through to the rear rank). They could be good against heavy cav which generally are 5+ save, but they can't stand and shoot so tend to get the worst of that. I haven't been able to find a decent use for them and generally don't take them, they are not as good as a unit of archers in my opinion.
Of all the rules in warmaster I think light artillery is the one which doesn't work. I know the Bournemouth guys who play a lot of the WMA and maintain Rick's site now have their eyes on updated pike phalanx rules and house rule it at the moment, but I think these need looking at.
Possibilities could be to increase them to 3 stands to give them an extra shot (for a modest pts increase), or giving them a rule in the roman army to reflect their combined arms usage in the legions. Some way of negating their penalty of being unable to retreat (and thus being wiped out if anyone basically contacts them)?
Let me know your thoughts on light artillery