I'd flip a coin. Honestly you wouldn't be wrong with either, they're both top tier prospects with the only real knock against them being shot mechanics. Markelle Fultz is really the only clear standout of this already very talented draft class in my opinion, and I'd put at least 4 players in the tier directly below him, including Jackson and Ball.
Part of me does wonder if the Suns would shy away from going with a PG so early with how much they trust Bledsoe and want him here. He's incredibly underrated by the national media and it's hard to knock Bledsoe for being injury prone and having bad knees in favor of Dennis Smith Jr, who has already torn his ACL.
I love the idea of Jackson on the Suns, and not just because he's a Jayhawk. I've said it multiple times, but I think he would be the most impactful, versatile defensive player on the team the day he gets drafted. Not to mention he has elite athleticism, the ball handling skills of a guard, great court vision and passing skills, very high basketball IQ, and a soft touch around the rim. It's cliche, but he just
wants to win and be great so bad. You rarely see top tier prospects like him that do all of the dirty work on defense, attack the boards, always hit the ground going for loose balls, are always focused and in top gear, play unselfish team basketball, and do all of the other subtle things that make you win games. If Kansas was his team (like Wiggins) instead of Frank Mason's, I think he could easily be a 20-8-5-2-2 guy for them. Even now Jackson's Per 40 stats as the 2nd/3rd option on offense are 21.5 pts/9.6 rebs/4.4 asts/2.2 stls/2.1 blks. The jump shot will only improve when basketball is his career, hell even Bill Self (who is one of the best and more honest coaches in college basketball)
has only had glowing reviews of Josh Jackson, namely his on work ethic, coach-ability, and passion for learning the game. As long as he gets his 3-point shooting in the mid 30's then he'll be fine, because he doesn't need to be a knock down shooter to contribute when he can do literally everything else on the court at a high level. He's Scottie Pippen-esque, not to say he will definitely be that caliber but he definitely reminds me of him at times.