1. The new menu isn't bad per se, but I miss the colorful old menu from XB360, with the gunfire and everything in the background.
2. Campaign is great, but the multiplayer experience is leaving me wishing for the old days. The unlock system doesn't feel rewarding, like, not one bit. Seeing all that armor locked behind boring (yes, as in LACKING the flavor of the old rank system) seasonal ranks leaves me with major FOMO. I want the system to unlock at my own pace, a logical tree of unlocks that I can get with in-game credits. I want to earn armor by playing the campaign too! Not feel pressured into waiting to connect over a patchy server to play a game, unlock an unlock, repeat.
3. Customization in Reach was a deep experience. It was rewarding. All players had a good idea of what it took to unlock that armor set - the rank, credits, etc. It's not as bad as the REQ system, which made armor virtually meaningless, but getting armor doesn't feel like an achievement anymore.
Also, I saw that the old credit system was apparently "optimized for XB360 architecture". Dudes, the entire GAME was optimized for that architecture. Exact imitation of the UI elements aside, if you can port the whole campaign over, I don't see why you can't rebuild a reasonable semblance of the credit system. Players have a bad taste in their collective mouths over season/battle pass/multi-exclusive/random unlock systems.