this mechanic is not backwards. if you can win with no units just so you can keep your income at +300/min go right ahead.
you have to build units to win games. you dont need any more reward than that. increasing mp income when you build units would be extremely broken. spamming infantry would make it easier to spam more infantry.
Maybe this mechanic might even be better than the vCOH mechanic. However, it still doesn't change the fact that there's a certain degree of annoyance that comes with being penalized income for every unit built. I'm pretty sure a lot of people feel the same way.
I never said increasing mp income for the promotion of spam fests, but rather, upkeep penalties should be kept to a minimum. Why in the world would having a late game army justify a minus 3 digit upkeep penalty? It's ridiculous.
Personally, I would jam the upkeep levels down, maybe there are better options, who knows? I just know that this mechanic should be fine tuned a bit because currently, it's just plain annoying. Plus it wouldn't skew balance in any way shape or form.
Players shouldn't be fighting against the game, they should be fighting other players.