J-11B is probably superior for A2A purposes. Until when J-10 and J-11B finally shows mature PGM and ASM integration, the JH-7A along with the Su-30MKK/MK2s, are China's only true multirole fighter bombers. Well that is overstating it a bit, since the JH-7A is more akin like the Su-24 or F-111, but it's a bit more fighterlike than the other two due to its fixed wings and tandem seating.
The best comparison to a JH-7A is an updated F-4 Phantom in the fighter bomber role.
The JH-7A has a few things going for it against the J-11B and the J-10. One is that it has a high wing configuration, which allows you to have more space in the pylon. You can put a larger missile there with less concern about ground clearance. The J-10 may have a higher payload weight capacity, but the space under the wings isn't quite as good as the JH-7A's.
Another thing is that the plane is optimized for low altitudes. Fixed inlets for example, is better at this. It is interesting to know how smooth the plane rides, vs. the J-11 and the J-10, that is important for bombing accuracy.
I do think that once the J-11B manages to integrate PGMs and ASMs, the JH-7A will be in trouble. No doubt the J-11B has better range, better ability to defend itself, more payload and not the least, the capability to install an even larger and more powerful radar for better range and resolution.
But so far the JH-7A is enjoying a valuable window of opportunity due to the quirks of radar selection between the two aircraft. Unlike the J-11B and the J-10, the JH-7A selected the JL-10A radar that was developed to be truly multirole in the first place right from the get go, while the J-11B and the J-10 picked the NRIET's KLJ series that appeared to be optimized for A2A combat but still lacking in air to ground capabilities that are only promised in the future. In other words, the KLJ series radar were developed not unlike those in the F-15, Rafale, F-16 and Typhoon, where you get the A2A capabilities out first, then worry about the A2G capabilities later.
The other question remains why not develop a J-11 using a variant of the JH-7A's JL-10A radar, perhaps a two seater. It is interesting to know, and quite theoritically possible, but unless we can put the entire program into a microscope, we don't know if they actually have done this. I heard a report that the J-11s were testing two kinds of radars, and Phazotron indeed disclosed that two Chinese firms are competiting for the same contract, no doubt NRIET and LETRI.
But would it be possible to accept both? One might have a single seat version with the NRIET radar for A2A purposes, while a double seater can fit the LETRI radar for A2G purposes. But its kind of an awkward way to do it unless you really desperate. The cleaner thing to do is get the better radar of the two in A2A, then gradually integrate the PGMs and ASMs on it.
In the case that two seater J-11 matures with having multirole capabilities, it will probably be the end of the JH-7 anyway, regardless of Xian's proposals to upgrade it (JH-7B?) via WS-10A engines for example. Xian's aircraft production capacity should be turn over to the two seater J-11s.
I got something to think about the Su-34's side by side seating. I don't think it's that smart of an idea when it comes to air combat, as I don't think it offers the visibility of tandem seating. Whether China can best be served with dedicated bombers rather than multirole fighters is still subject to heavy debate.
I suddenly have a thought about the upgrades. What if China decides to take one of the original Russian made Su-27SKs and UBKs and upgrade it to J-11B standards? They probably should have seriously considered it already and I won't be surprised if they played this on one or two planes. If this is a quick way to boost a force, you might just go buy many of the mothballed Su-27s in both Russia and former Soviet Republics at a cheap price, then overhaul and upgrade them.