If you would only be able to place bombs right next to you, bomb PvP would not be possible.
For distant objects you have orbs/arrows. Bombs should be a bit stronger too then if you reduce the placement range, so then they are high risk but high reward. (Suggestion: Increase damage to 10k + burning. Also change trebuchet recipe for demon fire barrage: 2 explosive jars → 1 explosive jar)
Also this:
And that: