Its an interesting idea divverent. I would also welcome to see more ideas or at least reasons why it should not be changed in any way.
So I think we could split the topic into 2 parts (I edited the mainpost again):
1.) Balancing the Armor / Megahealth compared to the damage output of the weapons. -> Is it needed?
2.) Improve the MH somehow or create something new which is not as strong as quad, but more useful then the current MH(see divs post) - > If you had the choice between the armor or the MH, most would take the armor. GreEn`mArine pointed me at the map final_rage, to call one rare exception.
ai wrote:Just because the Mega health seems worthless doesn't mean it is. I use it all the time strategically whenever I can and it can save anyone in many situations.
Of course, I grab it also if I can, it is an 100 healthboost. But compared to the armor it is weak right now.
ai wrote:Because You get an odd number from one Nex shot when you have 100 health and 100 armor? I really don't see any point in changing anything.
You get a odd number after these changes, too

It is also an very small change (30HP), which makes itemcontrol more useful. Dont forget that such a small change will also weaken the nexgun (nex/mortar Combo = 195 dmg). The nearer you can get to your enemy, the weaker the nexgun gets.