First, when you talk about the F-35, it's mission and capabilities, you have to almost have to forget about traditional aerial warfare. The F-35 is basically a supercomputer wrapped around an airframe that gives the performance of an early model F-18. There have been other weapon systems and technologies tied into it's development and deployment and that has to be considered as well.
Cost? It's expensive but some of the bad press has been exaggerated. Right now an F-35B will run you about the same price as an F-22 (if the production line was still open). Delays? Who's production line are we talking about? There were delays in the US but also understand that the Pentagon has to approve schedule delays and cost over-runs, and some of those overruns were due to the customer base asking for additional requirements.
The F-35 is a game changer and as it matures it will continue to quiet the critics.
Now let's see how the press greets the B-21.