I haven't done any Epic for a long time, but just poked in, and am curious.
What is the main reason why you want to do this? Why not just play Epic 40K? Is it consolidation, or so you can make changes? Not criticizing, just haven't figure out the motivation.
My first impression was that you wanted to make a new version of Epic 40K consolidating the addenda. But the changes you are making are fairly major, not tweaks. So I'm confused.
I think that when AT weapons get allocated front to back, they don't need the extra cost.
If you can find The Titan Project out there somewhere, that was intended to be a fan tweak to Epic 40K. It varied war engine weapons, while keeping the same simplicity of what was there. Mostly a few more trade-offs between firepower and range, that kind of thing. I think we switched some fire arcs for war engines, which I never liked being 180 left and right--we just pivoted them so they cross in front and leave a vulnerable spot in back. Might have made a few more changes.
Since then I have tried bigger changes. I wanted to quit measuring 6mm figures, so I tried 4" or 6" hexes. Changed blast markers some. Tried to unify CC and FF. The rules all "worked", but I didn't make a point to bring in some of the game stuff that made E40K fun. I forget that having movement and shooting rules isn't enough to make a game exciting.
Anyway, good luck. Just wanted to see if I could figure out what you were trying to do, and suggest you look into The Titan Project. I _might_ have the document around somewhere, but am not sure.
andy