So you want it to be a copycat of one of the other bomb spells? Instead why not just bump the damage up enough to be a little ahead of the other 2 on single target. Having a cast time will equate to less uptime on high movement fights and therefore limit it from being the goto choice. That way we actually have difference and individuality in spell selection. I understand that in pvp you can't have it hit that hard (burst rules) but pvp already has individual % tweaks to each bomb just lower it's % until the pvp crowd is happy.