Initial Problem..... EVERY BOOK NEEDS MORE GLUE!!!
For the Empire:
Greatswords ... a large template.
Regarding greatswords, who needs banners? What banners are missing you would like to see. Its not the greatswords you have a problem with it is the banners.... and there i agree. More banners, not neccessarially more powerful, but more options.
Master Engineers suck. Even if loaded with hochlands, they only have a bs of 4. For a shooty style hero, his bs should be on par with an outrider champion. They should also have the ability to take some forms of magical items. Why take a hero with no ability to tweak him a bit.
Regarding halbrediers, they should be bought as an upgrade to a unit like nets for goblins. Technically, that's how they worked. Drop them from the second rank and split the helmets of their foes.
For knights, remember you have the preceptor option. They are suitable for my needs, I go for simply removing rank bonus and wipe out my opponent on combat rez if possible. Against units causing fear, they are more than effective against undead while also being a threat against standard core units.
I like your hellstorm suggestion, however i dont take artillery anyways as you are left defending it.
Its the handgunners that need a good beating. They are simply ineffective against other ranged units. I'd rather take large units, soak up a few more casualties and crush em in close combat.