It doesnt sit well that civilian cultists are firing Space Marine statistic wepons at good range, plus I would prefer to keep it cheap and have more of a horde feel to it.

The only other list they're in is LaTD, which in my view is a total mess of a list. I'm not willing to compromise this list for a weak veneer of officiality.

It already is a cheap horde, I just don't want it to be a useless cheap horde.

ML are not just a marine weapon; guard autocannons are identical. My guys only have one on every other base, like guard, and have lower FF.

The aircraft are directly copied from the mossinian list; they're the established stats for a PDF airforce. They're meant to be weak.

A few new ideas for the next version:

Change Civilian Vehicles to 2 for 25 points as it's the only non-25 step in the list.
A formation of just Civilian Vehicles, say 6 for 125 points.
Cult Bikers, something like 30cm speed, Armour 6+, CC4+, FF6+, no weapons.
Genestealer Ark: War engine, basically a tougher, slower Patriarch.

they are actually in the 2012 compendium under
STIGMATUS COVENANT CULTIST CHAOS ARMY
SPACE WOLVES SPACE MARINE ARMY
ALPHA LEGION UPRISING CHAOS ARMY
DAEMON WORLD CHAOS ARMY
KHORNE RENEGADES CHAOS ARMY

sorry for the caps, I just cut and pasted from the list

the space wolves and khorne renegades don't have them, the others do as a standard transport for cultists.

A few new ideas for the next version:

Change Civilian Vehicles to 2 for 25 points as it's the only non-25 step in the list.
A formation of just Civilian Vehicles, say 6 for 125 points.
Cult Bikers, something like 30cm speed, Armour 6+, CC4+, FF6+, no weapons.
Genestealer Ark: War engine, basically a tougher, slower Patriarch.

A few other ideas:

Patriarch loses Supreme Commander, Magus gains it - At the moment I struggle to see reasons to take the Magus, and the more I read, the more it seems like it's the Magus who's the strategic commander, with the Patriarch as more of a revered figurehead.

A few other ideas:
Patriarch loses Supreme Commander, Magus gains it - At the moment I struggle to see reasons to take the Magus,

Teleporting Genestealers (and possibly other formation types)
Allowing Garrisoning for any formation with at least 50% infantry.

For gameplay this might make more sense. It runs contrary to the original fluff, but is definitely in line with more recent work.

Some other bits that may be crafted to serve a purpose in Epic are the Cult Icon Bearers, Cult Roughriders, & Cult Relic. Given the psychic power of the Patriarch/Magus, maybe some sort of arcane psychic weapon would even fit in.

I think this is a good move. It should almost guarantee that the Magus is taken in every force. In doing so however, please reduce the Patriarch's points. I would even expect that 50 points is acceptable for that model now.

When the list (v0.5) comes out, then let's see if we can break it