I always liked the idea behind the Lightbringer, brush is pretty scary to venture in as an ADC (as a ranged one, anyways) and causes running into brush to be a get-out-of-jail card more often than not for melee champions. Which is fine in Summoner's Rift, as most of those champions are at a disadvantage lanning, but in Dominion with all the action it's nice to have.
Beyond that you actually have to attack however you want to reveal and be all-out aggressive, and if you fallow a target into brush you were likely going to win the engagement in the first place. It doesn't help at revealing stealthers that are utilizing stealth to ambush you, just to escape from you, so I don't see a problem with stealth champions there. And for the stealthers that utilize it more to catch their breath and re-set cooldowns in the middle of a fight (Akali and Wukong), I've generally found Oracle's Extract to be an infinity better buy. For Kha'Zix, Evelynn, Twitch, Shaco, Talon, and Rengar it doesn't help against their ambush tactics, it only helps when they try to run away from a lost fight - which is a feat in and of itself for most champions that actually pick up the Lightbringer. Other than that it's handy at keeping a 550 ranged attack 550 range rather than 125 concerning the jungle.