Can you explain how TVC helps in BVR combat?
When you are flying at high altitude and high speed (the way to make your BVR go the farthest and be the deadliest, with a large NEZ - no escape zone), you can use thrust vectoring for greater maneuverability at altitude.
This is because your wings are less and less effective as the density of air decreases. At 40K - 50K feet, you have a small fraction of the density at sea level. At this altitude, your wings are considerably less effective.
Small winged aircraft like F-35, JF-17, even F-16 are at a serious disadvantage against aircraft like the Mirage 2000, Rafale, Eurofighter.
Mirage 2000 has weak engines, so does have an advantage but cannot fully utilize that aerodynamic advantage.
The British built the Eurofighter to fight exactly this battle, while the Rafale is a compromise, so less effective. The British use specially designed engines that are optimal for high altitude high speed combat at altitude, meaning in a real world conflict, they will have the capability to shoot the furthest AAMs and have the best survivability against enemy AAMs.
The Eurofighter however doesn't have something that the J-10 is introducing - thrust vectoring. At altitude, when your wings are not as efficient and your aircraft is being flown like a battleship with a very long radius of turn, thrust vectoring helps not only with ITR (instantaneous turn rate) but STR.
Added to the delta wings already better turn rate at altitude, the thrust vectoring significantly augments it.
Think of it this way - modern SR-AAMs use thrust vectoring for maneuverability. Even though AAMs have tiny wings, they can get excellent maneuverability and ability to turn on a dime. This is because of those thrust vectoring mechanisms they have.
There are many other benefits of thrust vectoring but it is yet to be seen if anyone other than the F-22 meaningfully field, operationally this capability.
Some of these other benefits include:
1. Ability to minimise use of flaps, aelorons, flaperons, stabilizers, thus decreasing drag and decreasing combat RCS
2. Increasing aerodynamic efficiency of flight at altitude.
3. Increasing ability to maintain stable, controlled flight at altitude.
4. Increasing fuel efficiency of cruise at various parameters due to better aerodynamic profile now available due to thrust vectoring
.... other stuff you can ask an aerodynamics expert about.
(And I have not even touched upon pre merge and post merge WVR advantage, mainly sticking to BVR at high altitude and high speed).
