Re: PLAAF new JH-XX / H-X bomber soncepts
Covered that in number two, the most efficient configuration. But then why choose a super sonic? I mean if you can do a super sonic stealthy bomber you can do a cheaper subsonic stealthy bomber. The answer is the mission role, that is defined by doctrine.
Stealthy supersonic bomber that can reach second island chain would be far more useful for the PLA than a subsonic stealthy bomber even if the latter is far larger.
Usually it's difficult to integrate speed and stealth especially on large aircraft, you choose one or the other.
If it's speed but no stealth, then you effectively have a Tu-22M3 or B-1, Tu-160 type plane. Massive punch, long range, and can escape from interception, but easily detected.
If it's stealth but no speed, then you have B-2, a difficult to detect bird but lacks the performance to GTFO if it's caught by enemy aircraft.
PLA will face both CVBGs and JSDF fighters and AEWC between first and second island chains. Airspace will be saturated with fighters and surveyed by all manner of radar. To deliver a payload through all that and get the plane back out alive, they need stealth and speed.
Thankfully they don't need such an aircraft to have strategic range, and can keep its combat radius relatively confined to the second island chain (air refuelling would of course increase it), so the engineering challenges of combining stealth and speed aren't as great (but will still prove formidable).
A stealthy high speed long range striker holds many missions:
-anti CVBG/shipping. A four plane formation carrying each with a few YJ-12s internally can ruin a CVBGs day.
-long range strike. internally carried LACMs and stand off weapons could penetrate a highly defended airspace and strike at targets. If we are looking at Japanese held islands with AShM or SAM launchers, a stealthy striker can get in and get out with near impunity against current and future generation systems. A modern Tu-22M3 or F-111 with modern stand off weapons and ECM are already formidable opponents, if the same kinematic performance and payload can be packaged in a VLO plane then interception becomes all the more difficult
-long range interceptor duties/missile truck. I'm sure an internal bomb bay can carry many PL-12s. Linked with a large attack AESA (assuming it has an air to air mode), such a plane with a large radius of action can support front line CAP with missiles. A stealthy, slightly smaller B-1R in effect.
-then there are more mundane missions like recon, ew, testing new generation weapons, etc.