After Looking through the internet i couldnt really think of an elite unit for the laketown subfaction
so my idea was to maybe make the archers into an half elite unit and Change their ability to an active or passive Damage debuff
the black Uruk archers from the cirith ungol Settlement have Pretty much the same ability so maybe Change their Damage reduction to an armor reduction, which would align them more with the black Uruk Warriors or make them redundant to them i dont know you have to deciede that.
But a damageredution for the now stronger laketown archers would help ered luin to tank through more Damage
since it was stated in the original ered mithrin post from Long Long ago the dwarves from the Grey mountains are, in contrary to the allied men in no need of Leadership from some hero Character. So i thought About making atleast the archers a bit more reliant/stronge through their heroes or their respective Town itself.
The additional Passive for the Dale Archers is a bit mundane, i admit that but as you stated sometimes less is more.
But Abit of Extra Reach is not to underestimated and underlines Dales more direct Approach through direct Damage when compared to laketown.
So Again i would suggest something like +15% Reach "Elite of Dale" Passive in the vicinity of Brand and Dale.
This new Passive would double if the unit is stationed in Dale, as it could be for the Laketown Archers.
so now instead of a "weapons switch" for Damage and armor debuff just give the laketown archers the Black Uruk Archers Ability and Name it something like "butthead arrows".
Their Debuff would increase in the laketown with the extra fortification upgrade making laketown now with their Stealth and tunnel and now also Damage debuff an even more hard to break Defence. And also doing it for different reasons than Dale would be now.
"Smuggled Arrows"
Passive
The Arrows of the Laketown Archers hit very hard. After Hitting an enemy for a Brief Moment they have a hard time striking with all their strentgh.
Hit Enemies loose 20% Attack Power for 10 Seconds
Bard is very familiar with all the different Kinds of smuggled ware and especially Arrows.
When in the vicinity of Bard or Laketown the Effect increases for 15% making it now 35% damagereduction
With the doubling of the Passives laketown Archers would do 50% damagereduction when stationed in Laketown.
That might Sound very strong but considering after outposts give 30% Damage for all allied Units or debuffing all Monsters in a large radius and so on debuffing one attacked unit for half their Damage sounds reasonable. Maybe the Passive could affect Rams also.
Oh and about the suggested moat for laketown maybe just make an entrance for every side of the town so even when next to stuff there will always be atleast one or 2 entrances to attack and catapults also can attack anyway. Laketowns weakness would simply be artillery
With more Hp and the Windlance upgrade Dale would be stronger when attacked with catapults. And for Long range warfare in general with the additional Reach Passive for Archers.
In any case please consider changing the Laketown Archers. Their current bombard ability with -20% speed and -5% armor feels kinda redundant to the swordsmen ability.
Also please check if the Men get the Smithing Bonus too. If not let them have some form of Bonus because as you said yourself they are a hard sell so their dwarven counterparts.
Btw Do the Towns of the Men get the Armor Bonus from the Stonemasons?
And since i still couldnt think of cool new unit for laketown id say maybe just give them a cheap and fast ram

Best Regards Voodoo