So it's funny, because what we consider hardcore is only savage and ultimate as the real content. I tried to find an analogy for how we view extremes. And the closest thing I can compare it for you is.. An extreme for us is like a fate to you and ultimate is an extreme. The spread of difficulty between those two are way too far apart that I wouldn't consider it even close to hardcore.
Here's a little more refrence. It took me and a group of friends 1 hr to clear an Extreme blind. It took about 72 hrs to clear ultimate with guides. This doesnt make ultimate 72x harder, but you can get what I mean.
If we take out extremes, we have only 14 fights in 2 years. And usually the 4 fights in a tier are cleared in at most 2/3 weeks. So in total, we got 21 weeks in 2 years for proggression. Thats not even 1/4 of the expansion time. Our solution would be adding 1 more ultimate in the expansion and we would be content. But as it is now, the game during the content droughts. The wait between 2 tiers is always the worst feeling in the game with nothing in between.