It has to be Wilder. No one could get by for so long on such awful technique without a very generous portion of physical talent.
Fury has the most raw talent, by some distance. Wilder is athletic and wild and powerful, and Joshua has a very solid amateur background and great physical prowess. But Fury has always been raw talent.
Joshua has the most raw talent Fury 2nd Wilder 3rd. I will say that Fury has the best-proven heart of the bunch, and for a big man when he's in shape, impressive stamina. All three has iffy chins, and not one of them has good defense.
:think Right now... at this particular time, I believe Tyson Fury has the better overall boxing skills out of these three. His balance can appear to be a bit shaky at times though, probably because he's so tall. He could definitely work on that a bit more in training, so he and his team may eliminate that issue in the future.
Long range stamina is a major component of athleticism. Fury has shown it in spades. AJ has not. Joshua is not capable of hovering round the ring in a constant fluid movement while throwing feints , jabs and body shots. Being muscular does not equal athleticism. Fitness , stamina , endurance , work rate are all factors of athleticism and Fury has the edge in all of them.
Fury's quicker but he's not as explosive as the other guys, they are quick and powerful which is a more impressive athletic feat. Also, what contributes a lot to Fury's stamina is the fact that he throws mainly slaps, he doesn't throw a lot of full blown power punches which are signficantly more tiring, he's also more loose and relaxed in the ring than either of them.
Wilder is far more athletic than Joshua and its not even close. He fought Stiverne entirely off the back foot , hitting and moving with decent coordination. AJ is flat footed , slow legged and has not shown any ability to box and move.
All three fighters are going to be refining and improving their games. Particularly AJ -- he's only had 16 professional fights. People are jumping the gun a bit prematurely on him following his easy dismissal of Martin. AJ is still just a work in progress. To some extent, this is also true for Wilder. His Pro career was fast tracked due to his daughter having Spina Bifida. The guy needed money to be able to afford to take care of her and look after her health. So he turned pro after having limited development in the AMs, despite taking home a Bronze medal. He's still gaining "on the job" experience, since his AM career was cut woefully short.
Joshua seems to have raw physical talent. Just extraordinary combination of speed/strength/explosiveness. But boxing is a game of wits. Boxers can become clever just like they can become strong, but some guys are just more "gifted" in the area of ring IQ, being able to box and being able to adjust and learn. I think Fury has that naturally, and has developed it. He's at home in a boxing ring.
Joshua is more explosive because he doesn't have to use the ring. Guys are right there in front of him. And not very good guys at that. He could not beat Wlad with that approach. It is only logical to put Fury first based on what he has achieved.