we had a thread about this by comrade Wiking recently
tidbits: The Germans waiting till July was so that the necessary number of panther tanks could be ready; however these tanks didn't perform well in their debut and could be sacrificed for a may or june attack favorably versus the amount of fortification work done by the Soviet rifle divisions in the sector
Von Manstein was convinced he could win the battle in May, and that it would be a tossup in June. Zeitzler, Kluge and Keitel where in agreement. Although of course Manstein favored a backhand blow
Guderian, Speer and Model where utterly convinced that it was doomed and should be canceled
Short answer, there is no POD after Stalingrad that gives the Germans any serious chance of maintaining the initiative for any significant period of time on the eastern front
Long answer, Zeitzler's plan was unworkable. Even if Army Group Center and South's mobile divisions could drive through and link up... the German army just didn't have the 12-16 fresh infantry divisions in reserve that would be need to crush a pocket of that size, with that many armed men in it. Also Manstein's backhand blow strategy, whilst probably correct given German advantages in long range gunnery and command staffs was inherrantly very risky, not only would the Germans be surrendering areas that had resources that where fueling their war machine, but also there was no garauntee that the Soviets would attack where Manstein wanted them to. The front was over 2000 miles long, and they had already been trapped at Kharkov and Kiev twice, so its safe to assume they learned something about screening their flanks prior to headlong advances
Thats not to say that the Germans couldn't do "better" at Kursk; even to the tune of a tactical victory
several things would have to happen
1. Much more modest objectives have to be set... namely crush the soviet front and second line divisions, then retire back to defensive positions, don't drive for the horizon, those days ended at Stalingrad
2. The attack must be earlier so the soviets don't fortify so much
3. You can't have all the good panzer divisions in Manstein's sector; during the battle the 3 best panzer corps in the german army where all attached to army group south (2nd ss, 3rd germanic, and 48th) naturally army group south broke through and army group center (which had a stupid plan of attack anyway) got hung up. Having the center get hung up early allowed the russians to concentrate all their reserves to draw manstein into a battle of annihilation
4. The Germans have to have more infantry divisions in reserve; ideally by stripping norway and the balkans
5. Hitler has to release the OKH reserves at the height of the battle if the commanders on the ground need them. Hitler refusing to release 5th SS panzer "wiking" and the 17th ss panzer genadier division took the wind out of Von Manstein's sails at a critical moment, and he wasn't able to keep possession of the battlefield which cost him over 300 damaged, but still repairable tanks, including many tigers and panthers which where difficult to replace
6. Hitler can't call off the offensive at its height because of Husky, since troops in country where able to keep the advance pretty managable anyway
There are even small POD's that could change things. Michael Wittman's 13SS heavy panzer company knocked out nearly 100 tanks by themselves during the initial stages of the battle. He veared off the Leibstandarte's line of advance to knock out several batteries of 152mm guns (which he did successfully) and was quickly driving towards the sounds of massive fighting between the 5th guards tank army and the 2nd ss panzer corps
The 181st tank brigade, by accident bumped into Wittman's force and engaged him. Wittman and his company inflicted a blood bath knocking out over 40 tanks, but used up all their fuel and ammo and had to return to the rear to refuel and rearm. Had the 181st not bumped into him... perhaps choosing a different route of advance, or getting misinterpreted orders, Wittman and 14 other tiger tanks would have been on the rear of the 5th guards tank army and possibly been able to panic them at Prokorovka and leave the Germans in possession of the battlefield, and potentially leave the 2nd ss panzer corps (Mansteins most lethal formation) in tact, which would reduce the ability of Zhukov to obliterate the Germans in his counterattack