Well to increase the chance, have AOE SKILLS, high hit frequency skills, packsize . I mean it's still 5% but more explosives happen.
Also explosive works great on some build for exponential DMG like with fire build or so where if shock explosion each, the fire attack gets more powerful in the shocked enemy and it loops. Same with other elements.
Although explosive is generally great anyway. I think it could be a good tool to trigger poison cloud better nowadays.
Edit: stupid autocorrect ruin my posts.