Copied is a strong word. Why build my house with sticks when I can use bricks? Just because I used bricks doesn't mean I am copying you. We can have completely different houses built but you'd accuse me of copying you? There is, of course, and always should be a source of inspiration for every medium.
With that in mind I absolutly believe Halo should draw inspirations from other games. Many are the games who have looked to Halo for inspiration.
COD having Theater mode is isn't 'copying' Halo. Sites having expansive stat tracking in the wake of Bungie.net are not simply 'copying'. Copying is what's left to Zynga.
Personal Dax drops - Are these meant to be copying Care Packages from COD? They certainly don't sound too similar. I think they are a weird beast because it seems to draw away from map placement. What I mean by this is that there won't be a shotgun outside the base on Blood Gulch anymore or there won't be snipers next to ample sight lines. Instead, there seems to be a shift towards playing aggresively. Want a scattershot? You have to do something for it. Simpy happening to spawn near it as in traditional modes won't cut it. It also means I can't just walk over to the enemy's base and take their shotgun. I think these will certainly shift the focus of some playstyles.
To touch on global drops vs traditional spawns: This isn't in COD, right? Is this only worthy of mention if you think it's better than the 'classic' style? I am certainly willing to give them a go. We will no doubt learn the maps like the back of our hands. While I always love the first 30 second rush on good maps, I am definitely open to this idea of a dynamic opening. So, instead of simply always going for Rockets on Powerhouse, we will end up having plenty of possible 'plays' if you will.
We already know the locations are predetermined so that just leaves the players guessing what will spawn where. I am hoping the locations will be somewhat neutral but I could be wrong. I actually think there will be a great level of skill needed for these opening games, especially if the competitive crowd can see it like I do. Because the weapons aren't known, players will have a few seconds to pick a strategy and act on it. I think maps will change far beyond their geometry in this 30 second period. Heatmaps will be a little more spread out and if I am stuck playing Haven forever and ever, at least I will have a different experience each time.
So yeah, this could be a great addition. I stress addition because we can guess from 'classic' offerings that weapons will apwn in those modes.
Instant respawns - Lose a 5 second timer and get accused of copying COD? It's a stretch in my book. First off, the obvious. This won't be the case for Objective Halo which is what immediately says there isn't any copying here. Objective goes hand in hand for Halo with me. With that said, I don't know how big an impact these will have on Slayer. The Haven footage so far certainly hasn;t had any glaring flaws as a result of instant respawns. Players can still wind down if they need to but I think getting dominated on your own spawn will be less of a problem. I think this will cause attacking players to leave a bit of breathing room so they don't get overwhelmed trying to camp the other spawns. with mods to get shileds back faster amon oter things, I'm sure that kind of dominating attacking player will have their fix.
Universal Sprint - Being able to run faster than the norm at a penalty is something I've wanted for a long time. Counter Strike has been doing it for years and COD certainly took it a step further (so punny). CS and COD both do this well and there should be nothing stopping a dev from wanting to do similar things with their sandbox, assuming it allows it. Reach's mistake with sprint was the lack of a discernable penalty. With Halo 4 stunning players who get shot while sprinting, I think the shift we'll see will be to a more passive ability. It won't be the evasion tool it has been in Reach.
Perks - I honestly don't think these are nearly as defining and outright gamechanging as the COD variants. I believe Domino Theory when he says they are tweaks. They sound like artificial enhancers of skill. Skilled players will enhance their skills while using these. For lesser players, it could be the bridge they need to enhance some element of their game so they can better tackle other players.
The difference between imitation and inspiration is how you take what is there and make it your own.