I'm in for the testing.
Although I'll be honest, I don't want a general normalization of damage modifiers, and from what I see in that chart ( 0.7 explosives on armor) we will probably be going back to the age of the Heavy Flak.
0.7 for the explosive weapons that already deliver huge chunks of damage is a bit too high.
Since this was brought up though, here is an idea I had some time ago, was planning to send Muse a mail about it, but I think it's still a bit messy, but I'll post it here.
Typhon Heavy Flak Cannon: Increased magazine size to 4 (from 2), increased reload time to 7 seconds (from 5)
Echidna Light Flak Cannon: Increased magazine size to 6 (from 4)
Manticore Heavy Hwacha: Explosive damage reduced to 18 per shot (from 25)
Explosive armor modifier: increased to 0.45 (from 0.3)
Explosive hull modifier: decreased to 1 (from 1.4)
Piercing armour modifier: decreased to 1.25 (from 1.5)
Reduced chances of instakills, explosives more effective against armor, Heavy Flak becomes a better stand alone weapon, Mortar is now the definite close range explosive king, Light Flak keeps its killing power but rewards accuracy more, Hwacha's armor breaking power tweaked a bit so it doesn't get out of control with armor breaking, encourages usage of explosives to help with armour breaking by reducing the piercing modifiers.
What is needed, in my opinion, is more of a nomalization between explosives and piercing as you see above OR at least toning down the disabling element of the Gatling and the Mercury, turning them in pure armor strippers, since if you are to keep them specialized, at least for these kind of weapons that take down such an important component so fast, go all the way and just make them be just that, armour strippers.