I'm pretty sure at this point where we are at, they won't take away from Halo 5's team to fix MCC. So for that scenario I'd rather not see 400 Halo 5 is Borken posts come late October adding to the MCC is Borken posts right now.
As for hiring more, I think slowly but surely MCC is coming around with what they have now. Except for those Aussies, sorry Azaxx. Ranks are coming in now soon, and the game is pretty good in terms of stability in search times for most. Hiring more would probably just be a waste of money, and that's not just in M$ eyes. I think that would be a waste of money with it's condition right now.
I'll say it before and I'll say it again, Halo 5 is going to be the end all be all for Halo. After Halo 4, like it or not, there's much ground to make up. How much of this ground is permanently lost is beyond me, but there have been clear cut losses. Halo 5 has all the bets placed on the table, and probably like 343, my focus and hopes are more placed on it. They have deadlines, and I bet they wish they could push the game back too. Microsoft makes these deadlines, and 343 must abide. These Deadlines are the reason MCC shipped out in it's sorry state in the first place, and if they don't use the majority of their time on their newest game, you could possibly see some sort of a repeat.
I'm not saying they should drop all of MCC and never look at it again, they've already shown improvements, and the games obviously WAY WAY better than when it launched. However, they're not going to go to the extremes you're talking about to get there Caboose. It's not the #1 priority. It's a shame MCC came out the way it did, but at some point you can't dwell on it, especially while Big Boss Man taps his finger on the watch. Halo 5 has much of a chance as being delayed as a Snowball has a chance in hell.