I have played this game for over ten years.
I've never seen any realm using only infantry.
I in fact have never LED an infantry unit. I've used mostly archers since the beginning. I currently have some range 5 special forces, some range 3 mixed infantry, and have commanded cavalry numerous times in the past. But never infantry. Why? It didn't interest me, so I didn't.
The point is, that I've never seen any realm rely purely on infantry. The average I've seen is between one third and two thirds of a nation's army is infantry, the rest is archers, and then a few nobles messing around with the other possibilities.
Perdan and Astrum are two realms that partially break this. Perdan has very powerful special forces recruiting centers, even after the admins erased the MOST powerful one during the Walls and Recruiting Center Destruction Portal Stone Event. And Astrum has the best Mixed Infantry RCs in the game. So both of those realms have a higher percentage of SF or MI in their lines of battle. But even there I see plenty of standard infantry and archers walking around.
Yes, the infantry and the archers are the most basic force used by the vast majority of nobles. But there's never been any time that I've played when only one of those was used. 
XD
Westgard has good RCs of every kind, but not really exceptional ones. Oh, maybe no cav centers. And maybe some really, really good melee ones.
But we've got like 24k cs split into two mobile armies of about 10k CS each (other 4k CS is mobile that doesn't tag along).
One army is 100% R5 SF.
The other army is 25% R5 SF and 75% R4 archers. (estimated, I'm not their marshal so I can't check).
I've not seen another realm as lopsided for ranged combat, but I've nonetheless seen a number of realms that are still very lopsided for it.
Westgard hard it worst of all, but in general, leading infantry sucks. You hit the front line in one battle, then your unit takes huge damage, and you have to go back to your capital right away. Sometimes, it gets destroyed without even reaching the front. But if your realm overwhelmingly won the battle, odds are all the archers are fresh. They can keep fighting. Again. And again. And again. And again. Also less chance of wounds and capture. As long as the army wins, you can keep on fighting until wear and tear or gold or morale becomes an issue.
And that's how Selena Chénier became a 33 year old character with 894 honour, while those who really tried hard to lead infantry did not (and eventually gave up on it).
I wouldn't mind if infantry got an additional armor bonus against archers on top of what they already got, if it meant archers could better target the front line.
Heck, could it work based on training? If the attacking archers average 100 training, then they have a high chance of shooting exactly as many arrows as needed on the front row before targeting the second, and the lower the training, the closer the odds of it being what it currently is? With the current tweaks, it's not too bad anymore, but it's still sometimes annoying against monster armies.
Alternatively... hmm... could we grant a tickbox to the marshals? "Should archers overkill the front row: yes/no"? Marshals who tick the box use the old system, where all ranged troops fire on the front row only. Those who don't use the new system. This would actually sound perfect to me. Give them choice. Then screen units are easy to bypass by using the new system, but it's an actual tactical choice, so maybe sometimes they'd want to expose themselves to that risk anyways.
