I dont think that Ukraine or Bulgaria have to worry about their future.
Bulgaria: With Pironkova and Karatancheva two players who can make at least the top 20.
Ukraine: Next to Perebiynis and Vakulenko I would chose Vika Kutuzova, Olga Savchuk and Oxana Lyubtsova to break the top 100.
Israel: Only Shahar and maybe Maria Gugel can achieve some successes but none of the will ever reach the top 50
Really dont worry about USA, Russia, Spain, Italy, Belgium and Switzerland.
France hasnt that many talented young players. The same counts for Austria, Germany, Sweden or Canada