Quite right.
The same complaint is sometimes made against Thiago. But both men hang on to the ball for reason. It's because there's nothing on and they aren't willing to surrender possession cheaply with a speculative loft forward. Moreover they both have the technique and balance to hold on to the ball under pressure and change the angle of attack by exploring other options while they still have the ball. In the temporary absence of Thiago (and the permanent absence of Wijnaldum, who was also routinely accused of lingering on the ball) we desperately need Curtis Jones. Milly's a great player but he can't change his mind when he has the ball now. Hendo is great too, but he's also not keen to change direction when he - or the team - is cornered.
I don’t think the same complaint is made about Thiago at all, at least by me, Thiago alongside Keita and Elliot are the three players who always look to move the ball forward, by making incisive passes. splitting the lines in Thiago case, or little one twos and give and goes around the box in Keita or Elliots case.
I would always advocating starting Jones instead of Milner for the reasons you mention but as someone who’s watched him since 16 I do feel like he plays within himself on occasion and fails to impose himself on games the way I know he can. I don’t get the same feeling from Thiago which is understandable as we’re comparing one player at the start of his career and another player in the prime of it, Thiago even as a number 6 still takes risks, with both is passing and dribbling.
Going back to Elliot I think this is why I may be even a little harsh on Jones, Elliot is a couple years younger but in games at the start of the season was already showing a bit more decisiveness going forward, a bit more bravery and when playing with two DMs in Henderson and Fabinho I think a player who meshes this with work rate can’t go amiss, especially in the majority of games where the teams in the league would form themselves into low blocks and dare us to pick them off.
In time I think Jones will show a bit more of that confidence at least I hope, but again maybe it’s just me getting grips with the type of player he’s becoming at senior level, and not having expectations of the player he was in the youth and reserves team weigh on my mind, after all Wijnaldum was a technically gifted exciting number 10/ winger for the most of his career and came here and was almost the opposite despite him still being a top class midfielder at his best.
I just feel Jones from what I saw has more scope and potential to be something a bit more, but we’ll see either way.