None Very Happy I am not even sure they should build them, I would like more an hypersonic one.
The problem there would be that it would become a very very expensive bomber to operate... and lets be fair an aircraft the size of a strategic bomber wont be able to manouver very much at all... the g forces in a turn are magnified by speed so the faster you move the less you turn when you pull a 2g turn.
A subsonic flying wing type could have enormous internal volume to stealthily carry all sorts of very long range very high speed missiles... when your missile moves at mach ten or more then it covers 3km/s so it does not need to fly for very long to cover fairly significant distances... makes more sense to carry weapons that can penetrate enemy air defences rather than trying to do so in your "bomber".
A missile to do so is possible now and only costs money when it is used... which is once.
With a hypersonic bomber it is expensive all the time because you have to train and exercise... it wont matter that it uses cheap free fall nuclear bombs... because you only use them once...
Russia will have cheap to operate subsonic flying wing bombers and not so cheap to operate supersonic swing wing strategic bombers... they have a choice for conventional conflicts and would use both in a nuclear situation... what is not to like?
A supercruise flying wing would be interesting but low drag designs limit internal capacity for weapons and fuel which would both be needed for its roles.
F-35s would really struggle with supercruising targets and they are to be the primary NATO fighter... perhaps.