Moves like the one you mentioned (called the Pugachev's Cobra maneuvre) as well as its horizontal cousin (the Hook) are really not meant for combat. A Sukhoi loaded with missiles and other ordnance would not be able to 'stand on its tail!'
The main value of these theatrics is to show the capabilities of the sukhoi (and those capabilities are impressive), as well as to advertize the SU to potential buyers. Think of the moves as glossy advertising.
However it should also be noted that the sukhoi -27, and its variants, are extremely maneuvrable due to things like avionics ,digital fly by wire controls and aerodynamic instability! It is a big plane (slightly larger than the F-14) but it is still able to maneuvre in an exemplary manner!
Thus it is an extremely agile fighter.... but do not expect to see a flanker doing the Pugachev over the Bering straits with a full load of AA and AG missiles!
The USAF is extremely interested in UCAVs, but we are decades away from anything remotely useful (bad pun intended). The pilot provides the decision making, based on all available data. There is no way currently to data link the vast sums of information needed over a jam-proof, secure data link.
Also, advances in various avionics make the F-16/F-15 much more leathal & survivable than they were 5 years ago - and those upgrades are continuing. Air combat is changing rapidly - and almost everything I was taught in the mid eighties is now as useful as knowing how to load a gun via the muzzle.