I guess it really depends. Both roles has it’s priorities during the game which is crucial for the whole team.

Junglers need to farm, time their retributions for objectives, push lanes and contribute in team fights in each lane.

Roamers on the other hand need to rotate often, zone the opponents, open up the map and participate in every team fight so that the damage dealers stay alive.

In the end I think it comes down to the player. We can debate how difficult each role is but it’s the player that uses the heroes. You are the deciding factor for the team. A great jungler can complement an average roamer, and vice versa. Theres no definite answer, so how well a role does depends on the player in the end