Ok, welcome to the forum.
We aren't the official 343 site, we are the fan forum, so, don't complain at us because we are the fan forum.
Also, host changes at start because the host at the start is going to have bad connection and will change to make it better, im failing to see how that is a problem, not much changes teamwork - wise, just keep position, and you will be fine.
Some guests are better then party leaders, probably because the guests are at a friend's house and play it a lot more then the party leader, again, what is wrong with that?
I admit as well, the nades are OP, they need to be toned down a little, but, once you get use to the nades, they are quite effective to use.
Don't have a go at 343, 343 have barely even touched the game apart from the odd update or 2, so, don't have a go.
Also, bungie messed the game up if you're looking to blame anyone, they created it.
Have fun playing!