Thanks for the suggestion. My ranged units, rifle and bows are light units and I think they're alright that way.
I will make my spearmen medium infantry to test out and maybe lower the armor value. My order of battle will be based on GMT Games Samurai so they aren't too diverse (no heavy foot with pure sword units, no missile cavalry). But there is a lot of quality levels in between. The foot troops ended up as superior because they are superior in the OOB reference above. Some commanders have lesser quality infantry.
GMT's Quality rating ranges from 3 to 8 and I had to assign Quality and Elan based on the distribution of units in the OOB (bell-curve). So there infantry that will end up as superior. 5 and 6 are the most common counters so I put them as regular.
Here's my conversion. See if it needs tweaking.
GMT Own P&S Elan Elan
Quality Description Experience Foot Horse
3 Raw 100 50 100
4 Trained 150 50 100
5 Regular 150 100 150
6 Regular 150 100 150
7 Veteran 200 150 200
8 Elite 200 300 300
Another interesting notion is that in GMT Samurai, the horse units are not pure horse. They actually have spear foot troops accompanying them. I don't want to replicate this one.
In another note, maybe a mixed sword and spear unit will also work (60% spear, 40% sword) since it is generic. This may lessen the "spear wall effect" when cavalry charges head on.
As for mixed spear and arquebus, I though of it too but there aren't much riflemen to spread among the spear units in most battles based on the OOB source indicated above.