Everyone else is sharing their opinion on what they think will happen, so I will too.
First of all, I do not think it would be a mistake or a stupid decision, as some have said, for Brandon Knight, Terrence Jones and DeAndre Liggins to come back for another season. However, I do think it would be in each of their best interests to enter the draft and not hire an agent. This way, they can go to some workouts and get a feel for what they need to work on to improve their positioning.
Yes, with a lot of people coming back next season, Knight, Jones and Liggins could go higher than they normally would. However, nothing guarantees they will be a lottery pick. If they happen to have bad outings and slip, nothing guarantees them they will get paid. I believe it was John Calipari saying that an agent would be covering their payments until a deal is worked out, then they would be responsible for paying that money back, with interest. So maybe financially it doesn’t make sense to leave so early.
Another thing, who is to say that Knight, Jones and Liggins wouldn’t go as high next year. No one thought Eric Bledsoe would be a one-and-done, but he ended up going very high. Why? Because he went up against John Wall in practice every day. To anyone who says these players won’t improve enough to improve their stock, I give you Josh Harrellson. As we all know, Harrellson went up against Enes Kanter and that only made him better and a potential draft pick. Next season, Knight would be going up against Marquis Teague. Jones and Liggins would be going up against each other and the likes of Michael Gilchrist and Anthony Davis.
Ultimately, I expect 1 of the 3 to stay in. Out of the 3, Knight is the most ready for the next level. However, I wouldn’t be surprised to see all 3 come back, or all 3 enter and stay in.