Games Workshop should make the Imperial Guard like they do Horus Heresy

So that title may seem a little confusing to you

"Horus Heresy is a completely different game and campaign system? How can a single faction be made like a game?" You may be asking.

Well, yes, but that is not what I am alluding to. I am more so referring to what GW has now successfully done with Betrayal at Calth, Burning of Prospero, and the HH model line in general. That is to say: release base sets with extensive resin upgrade potential. Most common and useful base sets in plastic, less common yet still highly utilitarian in Resin.

How many of you are tired of Cadians and Catachans? Especially since Cadia has now gone the way of Alderaan? Remember when there was more to the guard?

Well there easily can be again.

Essentially do the following
3-4 core infantry squads in plastic. Something like:
-Catachan
-Cadian
-Mordian
-Steel Legion
Then maybe a resin squad or two of the same faction for veteran, heavy weapons or command elements.

Then produce MANY FW upgrade kits with new heads/arms or heads/legs etc. depending on what is needed to complete the look. Stuff like...
-Praetorians (mordian base)
-DKK (steel legion base)
-Elysians (cadian base)
-Valhallans (steel legion base)
-Tallarn (catachan base)
-Tanith (catachan base)
-Savlar (cadian base)
-Armageddon Ork Hunters (catachan base)
-Vostroyan (steel legion base)
-Attillans (steel legion base)

And they could go on and on with upgrades and transfers. And finally add variety back into humanity. This could also very easily accompany a campaign IA book with some unique rules for various guard forces, allowing a few specialized FW characters or kits to be made. Maybe expand on an iconic conflict, like the Macharian Crusade, which thematically would be right up FW's alley. They are really really good at that whole "Future History" sort of thing.

This biggest thing though it is replicating the lucrative and proven success of HH where they can keep warehousing, production and development costs down by using a common template yet support a wide variety of product lines (ie HH factions) at the same time.

I just think it would be really great to see more variety in the IG again, and to me this is the most efficient, economical path to do so and has a proven record of success in the form of the HH product line.