First, to clear some things up:
- “Now, according to the canon of the Halo universe many things were destroyed on the planet Reach, such as the DMR, Armour Abilities, Spartan 3’s, and every single skirmisher.” This quote is false, on all counts. I’ll start with the DMR. Contrary to what I’m presuming you believe, the DMR was not an experimental piece of equipment exclusive to the planet Reach. Rather, the DMR has been in service for quite some time (though this amount of time is not disclosed). The reason we don’t see it in any other installments of this franchise is because Halo Reach is the only game that sees the player working with Army personnel, rather than Marines. The DMR was replaced by the BR as standard issue rifle in 2548 in all branches of military except the UNSC Army. Again, Reach sees us working with primarily Army personnel, hence the appearance of the DMR. Point being, the DMR is actually older than the BR. It’s not new and experimental and exclusive to Reach. As for armor abilities, these were never canon in the first place. I’m not saying that they break canon. Rather, they simply literally don’t exist as technology in-universe. They serve only a gameplay function, not a function in canon. Think about it. Every Spartan can sprint without the use of a module to do so. In you’re familiar with the fine details of the universe, every Spartan can also lock their armor whenever they please. Master Chief did so to survive re-entry in Halo 3. My point is that armor abilities were merely a gameplay function to mix up the game. They were not all obliterated with Reach, because they’re not a real technology and each Spartan can do most of the abilities with or without a module. They could very well feature in Halo 4.
Next, Spartan-IIIs. These guys were by no means killed off with Reach. I can tell just by this claim that you’re really not familiar with the finer details of the canon, so I’ll run through some of this. Spartan-IIIs were trained on Onyx to be mass-produced suicide supersoldiers, etc. There were three companies of Spartan-IIIs at the end of the Halo trilogy. Alpha Company was killed in their victory in Operation: PROMETHEUS. Beta Company was killed during their victorious operation on the Covenant-held planet Pegasi Delta. The casualties, of course, exclude members of the companies specifically chosen for other things (such as Noble). Now, there was a final company: Gamma Company. As of Halo 3, their location is unknown. Not unknown as in MIA, but it’s literally a loose story end. Ghosts of Onyx sees the entire company graduate and leave Onyx, but little is known about where they were placed, etc. In conclusion, Spartan-IIIs indeed live after the events on Reach. In fact, the last graduating class graduated just after Halo 2.
Finally, Skirmishers. You have no credibility in claiming that they’re completely obliterated. For one thing, they’d definitely have a home world, right? All Covenant species do. I honestly doubt that the Covenant took every single Skirmisher off of their home world just to put them on Reach. It’s just not likely, and it hasn’t been confirmed. A more likely story is that a good portion of the warrior classes of Skirmishers were killed, meaning the overall species simply went back into relative obscurity for a few years (as they never appeared before the events on Reach either, implying that they’re a relatively small portion of the Covenant force).
“Based on what we know, the health and shield system in Halo 4 should be the same as Halo 2 and 3.” This is, again, false. Frank O’Connor has confirmed that the Master Chief is receiving some canonical armor upgrades in Halo 4, meaning there’s no conclusive evidence that would allow you to lean one way or the other with health, as we definitely won’t be having the identical MJOLNIR Mk. VI.
“The next big topic is bloom. Based on the fact that Halo 3 did not have bloom, we can surmise that Halo 4 will not as well.” That is absurd logic. Bloom is purely a gameplay invention, and seeing as Halo Reach is a more recent installment than Halo 3, despite being chronologically a few months prior, it is the best measuring stick for whether or not bloom will be featured in Halo 4. An even better measuring stick, however, will be seen in 343’s title update come August. If they do anything about bloom, we can use that as a measuring stick.
“The final big topic is Armour Abilities. All Armour Abilities were completely obliterated by the glassing and destruction of the planet Reach. There is a high probability that they will not be in Halo 4.” I already proved this one false, but I just wanted to reiterate that armor abilities are not in-universe devices that are pieces of the story. Each armor ability feature a maneuver most Spartans can already achieve without armor abilities. They are mentioned in no media. Bungie never said that they exist in-universe as actual, canon devices. They are simply devices to enhance gameplay, and could very well make a return.
And finally, please remember that anything goes for Halo 4. It doesn’t have to follow the rules. We’re not working in the realm of established canon anymore, as we’re looking at facing a new enemy force in a new time period with a new cast of characters, probably a number of years after Halo 3 (giving humanity time to rebuild, as Halsey said they did on July 7, 2589). This would basically mean that, even if the DMR, armor abilities, and Spartan-IIIs were all obliterated with Reach, humanity would definitely have time to engineer something similar, and we’re actually likely to see a whole new set of equipment. Forty years is a long time.