Hi, I partially agree with your suggestion, i mean nerfing spawner count is good idea, but not to single because it'll be too big nerf, i think optimal amount will be 3 spawners because game was originally designed to fight on pillars, not to stay on bottom or fight on bottom.
Regarding to non-subscription members voting, i don't really think that they'll implement that because server needs money to run uninterruptedly and that voting feature was designed for ranked players.
About item spawning outside active hotbar slot, i don't have any opinion because i never had that problem, but maybe it's important to you.
To rest of this suggestion, i fully agree with it.