The speed tethering capability is really a feature of the new OSX rather than a special feature of iOS. You'd have to (assuming as already mentioned in this thread) have a data plan that allows use of a hot spot (some older unlimited plans didn't support tethering without paying additional fees), and if you want to link your iPad to your phone, you'd have to manually setup the hotspot on the phone and setup the iPad to connect.
The new feature in OSX is geared to make ones life using a laptop easier while away from accessible WiFi. If you don't have the feature from your carrier to support tethering/hotspot on your account, it will probably prevent you from turning on hotspot mode on the iPhone (as of 7.1, you evidently can't activate a hotspot if your carrier/data plan doesn't support it). I don't think Apple is going to be circumventing carrier restrictions on hotspots, they're just trying to make it easier for those that have that availability.