I do, but mine are fantasy.
I take the attitude that all my historical games actually occur in a parallel dimension, one point removed from ours. So when I want to make changes like this, I just go ahead and do it.
My rule is this: can I come up with a plausible hypothesis that it looked like that? Better yet, is there at least some circumstantial evidence in support of it? If so, I do it and don’t look back.
As such, my EIR legions have small groups of skirmishing javelineers. The two periods before and after did and there is some circumstantial evidence than legionaires were told off for this role. It makes the legions look better and fight better, so I did it.
We get slapped around, but we have a good time!