Okay so I've been doing a lot of digging lately (which turned out to be quite the pain for the HRE in this period, because historians really seem to have an adverseness to studying the medieval German military, probably because the HRE was such a complicated mess and looking at somewhat unified states and Empires is a lot easier), and I have been able to find some useful information.
First I'd like to talk again about unit names:
Heerschild: Now this is a term that honestly makes little sense in its current use. The Heerschild was roughly speaking a legal document that determined the ranking of the feudal social order within the nobility of the HRE and I am not quite sure what the idea of it denoting a personal guard or retinue is based on. If you want to use a German word "Gefolge"(retinue), "Garde"(guard) or "Leibgarde"(body guard) would be more appropriate, otherwise you could just name the general's unit after the ruler it includes, like with many other factions.
Landwehr: This term starts denoting a military unit only in the modern period, coming into common use in the 19th century. In the Middle Ages a Landwehr was a earthen fortification that divided feudal lands and other territories. The proper term for the unit would probably be "Wehrbauer". These were peasants that were encouraged to settle in border regions which they were tasked to defend until reinforcements would arrive in case of invasion, in exchange for freedom from serfdom and certain dues. Equipment would obviously be rather light with a mix of glaives, bills and flails and later halberds as weapons, somewhat similar to the Saxon halberdiers in the Hungarian roster. Due to the constant instability and conflict within and outside the HRE they would probably be decently effective and experienced troops, but definitely on the low-end equipment-wise. The Austrian ones seem to have been particularly effective, apparently being a part of the reason for the successful defense against the Ottomans, so Austria could maybe get a more elite/better equipped version.
Dienstleute: These were privileged serfs that performed administrative and military tasks for their feudal lord in exchange for being provided food, lodging and certain privileges, forming a intermediary class between the peasantry and aristocracy. Militarily, they seem to have fulfilled a comparable role to sergeants as lighter but still well equipped cavalry and infantry supporting their feudal lord in combat. I'd suggest renaming the Aussoldner to something like dismounted/foot Dienstleute similar to the foot sergeants of other factions. Towards the end of the Middle Ages the term "Reisige"(roughly translates to travelers) seems to become increasingly common, denoting paid, usually mounted troops that join their feudal lord on campaign, I would suggest using this name for the tier 3 Diesntleute to reflect its increasingly common use and the decline of the ministerial system to be replaced with paid troops in the late Middle Ages.
Knechte: I'd suggest renaming them "Fußknechte" to identity them more clearly as foot soldiers, as "Knecht" can have a wide range of meanings in German. These would be the common, trained, but not permanently serving foot troops in contrast to the standing force of mounted Dienstleuten/Reisigen. Their main weapons are polearms, initially glaives and biilhooks, later either halberds or pikes.
Depending on whether you give the tier 3 Fußknechte pikes or halberds, you could give the other weapon to a urban unit. Like in many other European countries at the time, these were generally well equipped and organised, but would usually only fight for the defensive interests of their city, making them unreliable campaign troops. I would also suggest creating units specific to a few major cities, like is the case in the Swiss roster, with their own heraldry, colors and symbols, as urban troops took great pride in their urban identity.
So basically this is the changed roster I would suggest:
Wehrbauern: light polearm infantry
Fußknechte: medium polearm infantry (tiers 1 and 2), medium-heavy pike/halberd infantry (tier 3)
Diesnstleute: heavy melee cavalry (tiers 1 and 2)
Foot/Dismounted Diesnstleute: heavy melee infantry (tiers 1 and 2)
Reisige: heavy melee cavalry (tier 3)
Foot/Dismounted Reisige: heavy melee infantry (tier 3)
Miliz/Burgher: medium pike/halberd infantry
Another thing is that I am kinda unsure about the Trabanten. According to wikipedia a Trabant is a personal bodyguard or adjutant and I have found no mention of Bohemian archers fighting as mercenaries in Germany and would therefore like to know what sources the unit is based on.
And finally after doing some more research on them, I am completely convinced that the Landsknechte should be a HRE-specific unit. In the time frame of this mod and even well into the 16th century they were the standing army of the Empire during the somewhat stable rule of Maximilian I. and fiercely loyal to the Emperor.
I have also found that their distinctive look seems to have already emerged in the mod's time frame. Apparently the slashed and puffed style of their clothing developed, because they found the tight clothes of the late 15th century to be impractical in combat and derided to modify them to be more comfortable, and also as an expression of their emerging corporate identity. By 1503 their style of clothing was already causing enough controversy that their right to wear what they wanted was guaranteed by the 1503 Reichstag. I also found two pre-1500 images displaying the typical Landsknecht look.
Edit: Just to be clear I dont think that the whole unit should have this look, but I think combining this with a more traditional style could create a very cool and unique look. Like giving maybe around half the unit slashed and puffed sleeves and/or trousers and having the rest look like more traditional late era pikemen.
Also what are the "Marscher"? I have never heard that name.