the f-22 is Fifth generation Fighter, second generation Stealth/fly by wire/vector thrust system. And fighters are a special category. They are intentionally designed to be at the razors edge for flyability. Most aircraft are designed to be inherently stable. For a fighter that is a detriment.
the next generation of Tilt rotor aircraft will build on the first to deal with various issues. the stability, durability, and safety issues will be addressed, and improved...like every other type of aircraft. First generation fighters were prone to shedding their wings at the worst time possible, engines caught fire at the drop of a hat, pilots got doused in hot motor oil if there was a problem etc...
first generation airliners were horrible, they fell out of the sky,had carbon monoxide issues, had airborne fires, and were just plain unlivable for long flights. people arrived cold, exhausted, and deaf from engine noise.
The Zeppplins had an altogether different problem. The idea was too advanced for the materials of the day. the light metals and fabrics needed to make them work efficiently were too weak to do the job, and the materials used to gas proof the fabrics were highly flammable. The British attempt at a passenger Zep used gas bladders made fro cow parts...
Using modern modern materials and Helium which is now viable since the materials are lighter, stronger and less likely to leak gases. Unfortunately they were permanently marred by several spectacular crashes which killed nearly everyone on board.
The new Boeing plane has a lot easier road to travel since most of the trial and error can be done in virtual simulation. the materials have been tested on previous aircraft, and the engines will be built using several more generations of development than the aircraft itself.