I would still like to see a visual representation though.

It would be great to see a Runtherd class.. I would love to sick my horde against some enemy or even coordinate with a Mek to use shokk attack gun!

Or you just might maul someone to death with a particularly unfortunate grot

Please give us those cute little guys!!!

A quick thought I had reading this topic is maybe Gretchin as a support npc.
There'll be different ones which perform different functions to assist nearby Orks.
Assault Gretchin with mini-stormboy packs. Just need an Ork to give them a kick towards the enemy.
Ammo runts. If there's an ammo system in place, then this is self-explanatory. If not, then they could increase fire rate.
Tech grots for vehicle maintenance.
Could think of all kinds of things.

Take three grots in equipment selection to give you some kind of benefit (in line with grot oilers or ammo runts) and they can follow you around the battlefield. Then if you get wounded, eat them up for a cheeky heal.

Targit Practis.
Carryin' Ammo for da Boyz n Me.
As spare ammo for da Shokk Attack Gun.
Fer Puntin' purpuses.

An' my personal favurit.
Stompin on em.

I think it would be interesting for paid Ork classes to have a grot dedicated to a certain buff (IE reload speed, vehicle repairs, etc), that can be killed by the opposition. and eliminate the buff.

Or just killed by Orks who want a laugh.
But they should be inexpensive.

Grots are a MUST-HAVE for any WAAAAAAAGH. I'd see them as some defense npc's or maybe some companion that you can use as bait.