I happened to think about the CoD franchise, especially with the re, specifically about the games that had all the features to be masterpieces but were held back by a few flaws or design choices.
Personally, two games immediately come to my mind when we talk about high potential. First one is Call of Duty: Ghosts (my personal favorite CoD). I know this game gets a lot of hate, but I think the potential was insane. The hit detection and weapon balance were arguably the best the franchise has seen for its time. It introduced great concepts like Extinction, Squads, and dynamic map events. Unfortunately, the oversized launch maps and the campy meta killed its momentum. If the map design had been tighter, I think it could be remembered as a top-tier CoD.
Another one for me is Modern Warfare (2019). This game revitalized the franchise. The visual engine, gunplay, audio design, and animations were flawless. It felt premium. Yet, its potential as the ultimate Call of Duty was heavily weighed down by the strict SBMM, a lack of traditional mini-maps at launch, and map layouts that heavily rewarded camping over rushing.
Both of these games had the foundation to be the greatest but fell just short of greatness.