F1 : What's happened  to the Hyper/Ultra/Super tyres, and why are Teams so resricted on tyre choice anyway?

They're the same as before just with a different name.    

C1 to C5.     Ultra soft to a hard tyre

They restricted them for safety reasons and to help the spectators. The feeling was if you leave the decisions to the teams, the teams will always choose speed over safety. Now the decision for the best tyres is left to the manufacturer who will have more knowledge.

As for the rest. I hated it. I'm not a fan of the 2 tyre choice in races either. Its artificial. I'd like to see each team choose 1 tyre from a range of compounds and run that all weekend. Also we need multiple tyre manufacturers back.

I think it is a shame that all these other, older makes of tyres are no longer in use.

I suppose the powers that be want as level a playing field as posible.

I don't know what happened to the versions you mention.   Maybe they just weren't being used, by choice.