I got nothing against Joshua, and I'm not pro Wlad.
What changes do you think AJ could make to stop getting hit with the right cross? He spent the whole fight working on taking away the left hook (successfully), but do you think he'd be able to incorporate enough head movement to slip the Klitschko right? Or parry it? How do you see that playing out ?
1st... Come in lighter. I don't understand why Wlad opponents keep doing this but they come in heavy against Wlad. Wlad is quite nimble and has very quick hands, you don't want to... No, you can't be heavy on your feet.
2nd... Conditioning and keeping his head up. No more ducking his head down, a hard habit to break especially against a puncher, but the split second you react and take your eyes off of a guy with the intellect of Wlad, he'll set you up to do it again. I also think AJ was winded before he was knocked down... It happens, so mentally I think he's a lot more prepared in a rematch to deal with the pressure of a super fight against a living legend.
3rd... Feint, feint, and feint. Feint with head movement, shoulders, gloves... Keep Wlad out of rhythm. Don't go for a KO, let it come if it does, but just focus on boxing. Klitschko is too cautious to counter effectively. However, once he starts feeling brave and feels AJ isn't going to throw any heat, rush to the inside to offset any offense he wants to get off, land some inside shots if possible, make it a lil ugly... But don't let him get that comfortable. Again, he doesn't need to throw hard shots, just keep it fast and sharp.
4th... I'd prefer him to just move to his right and stay completely out of range of the right hand. Obviously Wlad will notice so AJ will have to mix it up by jabbing, feints, and just being 1st. He seemed to have no problem seeing the left hook, but it's still a 1 shot punch that can end a fight. However, I'd gamble on dealing with that rather than Wlad's right. Maybe counter a missed left hook with his own left to the body ( takes a lot of practice to get that weave & punch motion correct ) since he ducked under a lot of em.
Overall, just come in lighter, calmer, more focused on feinting and outboxing Wlad, It's indeed possible.