Redguard and Oblivion are the only two games that occurs right before the end of an era.
That's true. While Morrowind wasn't
thatI think the novels already cut well into the 4th era
It's pretty hard to judge exactly how far into the 4th Era it is if we don't know how long that era will be, since it seems that eras in the Elder Scrolls don't have a set length of time, and just change when some sort of major status quo changing event occurs. There's also no guarentee that future games will take place after the novels, I could certainly see Bethesda doing that and using the novels as a transition between Oblivion and future games, but maybe we'll instead get a game that takes place some time during the intervening years and events that take place in it will lead up to some plot points in the novels. That's just me guessing, though, I really can't say.