Where did ranked teams go? Can you just remove 5 man premades, and have ranked teams instead?

I personally have never played against a 5man premade in my dynamic queue games (unless I'm playing in a 5man myself) and don't have a problem with some people's elo being inflated because they queue as a bigger group. However the dynamic queue restrictions most make it very difficult for aspiring challenger teams to find good matches. From the Dynamic Queue roundtable video that Riot released recently (Gbay99 my babe), I can't help but feel no one cares about the removal of the odd Ranked Teams and the group of players it served very well. They talk about the possibility of removing the option of having 5man groups unavailable once players reach a certain elo, it just seems odd that Riot doesn't want to have to find games for people with insane elo in massive groups. Since the MMR cap of Master/Challenger can no longer queue with diamond 3/4/5 players (i think), I have friends that are a great cohesive team with ranks of:

• challenger -diamond 2 -diamond 3 -diamond 4 -unranked (challenger last season) This is effectively my uni's top team, but they can only play ranked if the challenger player plays on a 2nd account, and then it doesn't even matter because in OCE they will be waiting 60mins+ and then get paired against a bunch of solo diamonds and crush them to gain 3LP and no valuable experience. They then have to resort to finding other high elo teams or pro OPL teams and custom against them. It doesn't really help them get better as a team unless they scrim against the different teams each time. The main question I want answered is: Why did Riot remove Ranked Teams?