Question

he’s not great at handling the ball.

Scouts look at how well a person takes care of the ball.  (Ball Security)  This is what is mostly meant by ballhandler.  A person who doesnt make a lot of bad turnovers can be considered a good ballhandler.  

This is not to be confused with dribbling skill (handle).  

I am assuming you are talking about someone like Wroten, he immediately comes to mind.

Some guys rarely turn the ball over, that makes them good ballhandlers.  Others like Kendall Marshall turn the ball over a fair amount of times but because his Assist to Turnover rate is so good, he wont be considered a poor ballhandler, because he handles the ball about 38mpg and gets his teammates easy buckets.

 I think it means he Doesnt have many dribbling moves ie crossovers,spins etc and maybe is also not good at properly securing the ball 

 Probably means he has a weak left hand, can only really drive in straight lines and doesn’t have many go to moves. Doesn’t handle the ball well when guarded closely, picks up dribble under pressure etc….

 Shot creating skills off the bounce, creativity, ball security, and off-hand dribbling comfort? Thats what I go by, not sure about everyone else.

"doesn’t have "great ballhandling ability"" …. I think it depends also on his position on the court :

if he is a sg or a sf, it should mean he can’t make so much difference by himself and doesn’t manage to create his own shoot regularly….. and if he is a pg, you can add the way he brings the ball in offense, the way he limits turnovers by protecting the ball or not, the way he draws fools only by controling the ball.

I believe ball-handling ability depends on position.  Typically, you will see does not have great ball-handling ability when you look at scouting reports for combo guards. What I have always taken this to mean is that the player struggles going right or left, does not try to drive the lane, and when he does, will only look to score for himself.  I think that a lot of times if the scouting report is for a small forward, this typically means that he is a spot-up shooter, fast-break gunner, or a guy that plain scares you when he drives from the top of the key into the lane because you have no idea what is going to happen–I think of Shawn Marion in this situation; could be a dunk, a funky pull-up, a turnover, or a kick-out, but overall lacks consistency of good-decision making abilities–by and large, this Small Forward cannot create his own shot.  

As far as projected Power Forwards and Centers, I interpret "ball-handling ability" as the ability to face your man up away from the block and drive to the cup.  I guess I should say, it means this big man can play more towards the perimeter without the fans gasping "oh shit."

Overall, for a Point Guard, Shooting Guard, or Small Forward, it means you may be able to run your offense FOR this guy, but you cannot run your offense THROUGH this guy.