Not a bad choice - leaving the cost factor alone.
It all depends upon how much power/thrust do you want for a particular fighter that you want to design for certain role missions.
For example: When you want to design a heavy, all-weather, long-range fighter, how can you use a single engine alone? The F-16 has a single engine, but the F-15 is a twin engine bird. The twin engine aircraft allow for faster speeds, longer range & faster pickup.
The famous/infamous Israeli daring (Osirak) raid involved mainly F-15s.
Why did India (a low income country) chose the gas guzzling twin engine Su-30MKI as their workhorse?
There is more to it than what meets your mind.