The progression system that is in place, which consists of seasons comprised of 100 tiers each is one that doesn't belong in Halo Reach at all.
The primary problem with it is the unlocks make no sense compared to Halo Reach, let's take the JFO Helmet as an example. Said helmet is unlocked at Tier 59, that means season 5 and tier 9 of said season, this also means that you unlock it after 59 levels. However, in Halo Reach it is unlocked at level 20; Lt. Colonel. Truth be told this is something that doesn't take too long to unlock in the original Halo Reach compared to the MCC version. As another example you unlock the Pestilence armor effect at tier 52, and the UGPS wrist piece at tier 63. Meanwhile the former costs 1 million Cr in the original Halo Reach, and the latter costs 80k Cr. This is a massive price difference that clearly shows that something is wrong with the progression system in the MCC version of Halo Reach.
Another huge issue with the system is that it is so incredibly linear, if you compare it to the original progression system it was also linear, however in the original you could buy whichever armor you wanted assuming you had unlocked it or not. However a lot of armor is unlocked very quickly and you can therefore get your character to look unique even at the start, meanwhile in the MCC you have to for example wait till tier 11-20 in order to first start getting shoulder pads and harnesses, meanwhile in the original you got a bit of everything with each level, not only this but you also had a basic set of items you could buy regardless of level at the start. This makes it very difficult to customize your character in such a way that you want to.
To summarize this, the way in that it's structured is completely wrong considering how it was structured freely in the original game. Not only that but it's very difficult to make yourself a character that is both unique and something you like with such a linear progression system of acquiring more pieces of armor.