There may be a possibility to add a herolike officer skin to elite spesializised units.
Flagelants culd get warrior priest of sigmar as a officer, Swordmasters of Hoeth culd get a High Elf mage to illustrate their bodyguard obligation to the white tower. same, the spesial faction units of chaos culd get each factions hero slots as officers.

This wuld only be cosmetical, as they wont be "true" heroes, but atleast this wuld allow heroes from the table game to take part in the tw battles..