Well, independent developers work on a slightly different workflow then bigger studios.
It also verries from game to game, 7 days 2 die is independent game and it takes them weeks to months to patch, Project Zomboid is independent game and if it have 2 patches a year I consider it a success, then we have fuckload of minecraft clones and "terraria with different skin" kind of crap.
No one will convince me that adding new block to minecraft is equally "hard" as adding new asset to game like CoH.
Patching process varies greatly from game to game, I'm trying to compare CoH2 to projects of similar scale at my company and give a rough estimates of what it might look like for coh based on that.
Bottom line is, it takes time to both, implementing any new asset and calculate, implement and QA gameplay balance related changes.
Regarding big progress on older games, let me point you at WoW or PS2 alone, neither is a new game and both have problems of considerable size. Every single WoW update was bug and exploit fest so far for example.
Hell, I've seen features that worked fine for a year without mandatory maintenances, which turned out to be bugged at the end. So yeah, age of the game isn't really related to frequency of big issues-difference lies in how you handle them and how transparent are you with the community about it.
i want to see how long it takes to do each segment of the process and why each segment takes that long. id give a week, i wouldent give more than a week, again this is for something like; we found that this unit is way overperforming, we need to nerf it to have stats of XY and Z. if that is the ONLY thing you intend to do to move the game closer to esportsability. use that example to illustrate why it would take 3 weeks.