I have witnessed a rise in kickoff returns for TD's, also. Luckily, most of them have been from my team. I think what WarEagle says is accurate. I do believe owners are letting the AI set the depth chart. The change I have seen is the kick returner looks to be tackled 3-4 times and somehow breaks out of it. I rarely observed this before.
With that said, I've also noticed punt returns seem almost automatic. When the returner decides to run it back, it is around 8-10 yards almost every time.
I'd like to see more excitement on punt returns (not too much), and a little less on kick returns.