I believe Su-30s would still have some overall strategic advantages (not necessarily in a one-on-one combat) because of higher payload, longer range and more fuel. And AESA, long range BVR, ability to launch cruise missiles from standoff distances and 3D TVC will effectively balance out whatever advantages the Typhoon may have.
Well long-range strike is an area where the SU-30 does have decisive advantage since the Typhoon was never seriously meant for that role. If it does get conformal fuel tanks, it would be a bit more competitive but I think it’s overall range may be below the SU-30 or rafale. The Typhoon would still retain an edge in aerial combat as it is also slated to get AESA radars, the Meteor missile and probably also thrust vectoring engines (for which research has been done). The SU-30’s big size and older electronics/missiles do put it at somewhat of a disadvantage against newer fighters. Most new aircraft are likely to detect it before it detects them.