To accomplish this you need to change the mentality of most of the community. Right now, people expect perfection and they expect speed runs. If that doesn't happen, they rage quit. Making content harder will result in wipes and it will result in runs taking longer. This would require the dev to dig their heels in and say "this is the bar, we're not going to lower it"

Personally, I feel the normal mode raid is what should fill the gap between faceroll and savage. At one of the sessions at fanfest in 2016 they mentioned expert dungeons would stay like they are. They are meant to be something that can get done in about 20 minutes. Using the current ilvls, they should make tome gear 350, obtained by faceroll content. Kick up the difficulty on normal mode raids a notch and have it drop 360 and then have savage at 370.