Its not that simple. I see your point, but the shape of the aircraft itself is only one piece of the puzzle. In the same time they need good RAM material, at least basic passive sensors, perfect mission planning and such a things. In this case far better choice should be German Lampyridae design with much better aerodynamic characteristics (F-117 is highly unstable design that can fly only thanks to multiple backup flight control system, at least on the F-16 level) and also slightly better RCS, especially from the front. But Iran don't follow this option for a reason. Even if they succeed in building this kind of vehicle, it will still not be good enough to penetrate US or Israel and now even Iraq air defense.
They had the project of the advanced semi stealthy fighter called M-ATF, developed from the beginning of the millennium with the Russia. Later transformed into trainer/light attacker Shafaq and sometime in 2005 transformed once again into domestic M-ATF. But they were not able to proceed beyond the mockup stage without the external help. And it was very good design, based on the Mukhamedov work and in the Korean T-50/A-50 category, what is exactly what fits Iranian needs.
From the mentioned facts we can conclude, that 5th generation or at least semi-stealthy fighter is unachievable for the Iran without the external help. If we take a look on the weapon systems, introduced in the last decade, we can see, that Iran rely on the reinventing of the old, but proved and efficient designs, so for the next years I am sure that they wont have anyting better than F-14/F-5 combination. Maybe in the far-term future they will be allowed to buy stealthyfied version of the China/Pakistan FC-1/JF-17 fighter currently under the development, but I expect strong US lobby against it.
