He does lend enough to attacking play. Ox is abetter option when we require goals.
It is all about different tasks.
Ox = penetration
Gini = link play / defensive stability
You need 4 things from a functioning midfield. Protect Defence / Link Play / Create / Support Attack. Gini does all those things at a good level depending on what role you give him. Ox, you definitely want focused on those latter two things and I would argue he is the only midfielder we have fit who offers those things at a high enough level. So you want him in that 8/10 hybrid role.
In terms of linking play - you want someone who protects the ball well, can escape pressure and can complete forward passes in the opposition half.
Name Dribble Success Dribbles/90 Opp Half Pass Suc
Wijnaldum 78,85% 1,73 85,44%
Can 75,00% 1,03 81,08%
Milner 75,00% 0,29 78,16%
Chamberlain 74,07% 2,96 73,75%
Henderson 57,14% 0,38 77,17%
So if your midfield will be under pressure and you want a player to be able to receive, turn and play the ball forward to the more creative players - a deep midfield of Milner & Henderson is a problem. Neither is comfortable escaping pressure. Which results in teams being able to detach your front 4 and back 6 if they are well drilled in pressing - as we saw in the final against Sevilla when Milner and Can couldn't receive, turn and find any of Lallana, Firmino, Coutinho or Sturridge.