Yisroel refers to Yashar-El as in straight with G-d. The Yud is a reference to the the nature of Yisroel - Yisroel is locked in battle with his Yetzer Hara / the forces of Evil in this world. It will only end in the times of Moshiach/The World to Come, when the forces of Good will prevail. In this sense the Yud represents the future - that Yisrael will prevail in the future and be considered Upright with G-d. Notice how the name is in reference to G-d's name as used as a single force in the world - KEl. This is reference to din, or judgment. Din is Divine Justice - meaning in the future, when G-d's true justice is carried out, it will be clear that there will be Only One G-d, who will be righteous in judgment and Yaakov's progeny will be considered G-d's people - hence the phrase - Yashar-El.
The only person in this period that has two names that are both used in Yaakov/Yisrael. Yaakov means the heal. Just like the yud represents the future - so too, in the future, Yaakov will be vindicated, and be shown to be the rightful heir to the berachos and right of the first born. In the future - the heal will be shown to be really the head. Symbolically, the heal is revealed when you take off your shoes. The Neshama is compared to the foot and the shoe compared to the body, hence when we enter into service to G-d (Kohanim take off their shoes), we take off our shoes symbolically revealing our Neshama.
In the future, our heals will be revealed - i.e. it will be shown that Yaakov will be vindicated - that his true nature - i.e. that of the quintessential human being - totally in service of His creature will be revealed and the light of his Neshama will fill the world. It will be clear to everyone who is G-d's chosen people, through the heal - the revealing of our souls.
Perhaps we can understand the duality in Yisrael/Yaakov being reflective of championing over the yetzer hara, and revealing that inner greatness only in the future.
