Like I said:

"I like the idea, but I would think such quickly levied units would be of poor quality.

So, (conversely to your suggestion) imagine you just had 4 or 5 top quality units to deal with and now they are backed up by a unit of slingers, one of archers, a few hoplites and a crappy cavalry unit. Seems more realistic, and just as challenging."

It's a good idea, on it's face, my only contention is that the quickly raised militia should be third rate.