About Tiank: Well yeah this "bug" is quite normal because the stormingsystem works like "First row storms, second, third, fourth...." In this case, the first 3 rows storm, but they stop exactly at this moment because of the row infront of them

Just as explanation why (Probably you know even why

)
So changing the way of storming would fix this problem. Not sure what we could go for else? The game has to notice that the first row can´t storm(from the view of the flag) but the last one can, so they are storming "starting from the last row" Would sth be possible Lewin?
About the tiles: Hmm I didn´t want to believe when you wrote that the distance is exactly the same as in TPR, because sometimes in Multiplayer I really had some few troops running threw the whole map (Coastel Encounter), while others just stopped after a few tiles(probably because of an object). Nevermind I believe you then
However I would suggest sth like: 10-12 tiles The difference is the same with your suggestion about 12-14. However I just imagine, that it could be better to keep the minimum distance lower than these 12 tiles (In my opinion even these 8 tiles are perfect

), because the stormattacks right now have the perfect distance! If your ally needs help, you can storm easily to the battle and help him.
The main problem about this storming system is that it doesn´t work in most of cases (objects, Tianks example, animals, elavation? ). From these 8 tiles in the original game, to the 12 tiles in your suggestion, this would mean that swordmen for example would be more powerfull again

I don´t want to start here big considerations, but I just guess that horses won´t be that powerfull after you can storm with your swordmen, the bowmen of the enemies via clicking 3 times the storm button

(3 x 4 (difference of the minimum disctance) = 12 tiles extra )
My opinion about the idea of andreus:
It sounds interesting, because players would make more axefighters again (maybe) and it´s also logicaly that iron units can´t run that fast like leatherunits. HOWEVER I think we will have more new problems. It´s just the discussion with "How to bring the scout back". There was also the idea with giving scouts extra speed, but just imagine you can catch bowmen with these scouts, run away and noone will get you with knights

Same thing with Swordmen/barbs/milita/axes. Just think about milita or axefighters having 2 times bigger distance than Swordmen. I doubt, this will work particularly with your example

:
For example, 12+-2 tiles for iron and 15+-2 tiles for leather army?