If you have any concerns that the mere existence of LO aircraft around the globe may drive threat system designers to use different bits of the RF spectrum sometime in the next few decades, then you need to have the next bit of the countermeasures cycle ready - and in your weight growth and signature budget.
Give that man a cigar.
"Stealth" was a means of dealing with the problem in the 1970's and 1980's era tech of radar coverage of target areas, its intent being that "the bomber always get through." The tech had been in development for some time, yet by the time B-2 was fielded, the setting for which the requirement was established had morphed considerably. Fortunately, B-2 retained for a while some distinct advantages as a delivery platform versus a certain class of air defense architectures.
If military hardware history tells us anything, it tells us about technological advance/edge, counter, counter counter, and so on. (Granted, submarines are still about the best "stealth" platform yet to be put into the field, but they are not aircraft.)
It should not surprise us at all that between R & D, advances in math, and advances in computing power that a "counter" to stealth is at least in the works if not in a prototype stage.
This brings me back to JSF and B-2. B-2 was stealthy and in the field twenty years before JSF can hope to be IOC. The old saw about "building kit to fight the last few wars" screams at me.
As I don't know enough else about F-35 I won't comment, but that is the basket into which we (in the US) chose to put our eggs in the late 1990's. It's been the Fargin elephant in the defense acquisition room for nearly twenty years.
It has foreclosed, due to its budgetary impact, programs like Comanche and a field artillery system that other services ran up the flag pole. Bang for buck, we aren't sure what we'll really get.
It is the V-22 Osprey, second edition, with afterburner. (As a program).
Until it goes out into the field and operates, I'd not blame anyone, particularly a nation with a modest defense budget, for being massively skeptical about its bang for buck payoff as a core weapons system in the combined arms kit a given MoD has and maintains.