Yes and no on the data transmission ... it's all related in one form or another.
You are correct that data transmission (in general) does not include things (lag comp or rewind time or interpolation, etc.) required for this type of programming (gaming), but it's still tied together based on the transmission otherwise, one would not need the "helping code" to compensate.
And I do understand guaranteed delivery and fire and forget (TCP v UDP) and how each would be used in the various software layers.
You are correct, peoples memory (I'm included as well) does change over time. But I did a sitting last weekend and played one game after the other so not to try and recall from a jaded memory but from actual/recent memory/experience. For me (and what others stating), as I played each iteration of the titles, the game play became ... ummmm ... less pleasant. This was done using the same hardware and provider, no change there, only change (whatever they are) was from title to title.
And yes, as mac has pointed out many times in the past, the games are not the same, and I do agree with his statement. But something is off and for whatever reason, it just appears to be related to connectivity.
At any rate, I cannot state what it is (and I'm not implying it's one thing, it could be several things combined) but I know I'm not the only one that is frustrated with the current game play.
What appears to be the standard/canned answer from Acti and/or the studios is ... it's not our code/game, it's your setup. While this may be true (and I'm sure it is in some cases), my feelings are (and many others feel the same), it's not as much on the customers side as it is on the developers side.
But I'm willing to concede, it's the customers and not the developers. The problem with that is, I will at some point, get tired of the frustrating game play and move on (as others have) to something that gives me what I used to get with COD, and that is an enjoyable experience majority of the time, not the opposite.
And yes, I do need my head examined, I keep playing, but it's in hopes that things will get better. Oh snap, I think some would call that an addiction.