If you're going to try to Boom 1/2 HP mobs, all I can say is have a good healer. I re-tried hunting with my Boom in CT1 in the Skyshadow Meadow in hopes of a BW helm recipe. I could comfortable pull 4-5 groups with PP/SE buffs and a Bishop healing. Pulling as much s 7-8 groups got a little scary.
The trick is timing. Make sure you buff Boom with Empower,Acumen, and Zerk. Park him in a corner like you would if you were poling. Then grab a few groups. The trick here is to run to the corner with mobs in tow and set Boom to explode a couple seconds before you start attacking, that way he hopefully explodes right as the remaining social mobs charge up to you, but hopefully before they kill you.
Expect to take a ton of damage until you get the hang of it. The healer has to be careful not to heal too soon and draw aggro. You have to make sure you hit Boom just the right time so you kill as many mobs without dieing yourself. There are so many things that can go wrong with this way of hunting, it takes patience and diligence.
The radius nerf isn't that bad really. Generally the Boom tends to stand a bit away from the corner I'm pulling to. He ends up being pretty close to the middle of the group of mobs.
The only issue I have is if there are some magic casting mobs like the Luminun groups out in Skyshadow. They do get up to mele range but usually half of them stay back out of the way of the blast radius. Not a huge deal though; the majority of the group dies pretty quick.
Populator is pretty dead on here. Instead of before when we'd have boom do all the work while we sit back and rack up xp, now the roles are reversed. You'll want to pull/tank mobs while boom does his work, and normally this means having a healer to survive. I was out blowing up mobs under Giants cave a few weeks ago (now they are blue so cant anymore), and with a EE partner, we got it working pretty flawlessly.
Whever you go, it's all about timing. Pull all the mobs to a place where boom is parked, preferrably a corner (dont forget shots for him if needed). I like to start with whirlwind to hit all the group leaders and force all the minions in tight. The hard part is timing boom so that he blows right as the minions rush in, takes practice and is quite dangerous until it's mastered. Some locations to try this are Skyshadow meadow, Ancient battlegrounds, and under Giants cave for 1/2 hp group mobs. Also, I like Swamp of Screams for stakato groups (weak to fire?), but they are a bit tougher.
Boom isnt worthless now, but certainly isnt as great as the old days. I use it often in spots like catacombs or Silenos for added damage and faster kills when i'm the only poler...but be warned, if your using blessed shots, your probably losing money each pull...
big boom works great in catas if you use shots and have 1 or 2 other boomers with you you can pull a whole cata if you have a good runner/tank, just set booms in a radius of a corner have the runner drag mobs in teh corner and everyone boom, after booms blow have the 2 or 3 boomers use wirlwind skill to fining off teh leftovers and get soem nice overhits in.
also big boom can be use to kill raids much lower then yourself
not really worth it but i did it for a friend that needed a low lvl raid for a quest, all you have to do is stand far enuff away to not get silence as you summon if the mob is blue to you it will not try to atk you at all. this can also be done for bigger raid but would require you to have 30 or more boomers, and you must stand out of teh line of sight for the raid not to come after you.
Boom can also be use very well to solo fortress seiges, to farm knights and clan rep points not to take it.
all you have to do is take down the door, run the 2 mages out and kill them if its a large fort they will be posted behind the door. The big boom works very well on the archer groups in the middle of the courtyards, send the first boom in un shoted to take aggro off boom onto you, make shure your slightly out of range of sight of teh archers like just right outside the gate to the left or right, the next boom you send it the archers will not atk him and you can blow him up and kill off the archers( takes 4 to 5 booms to take them out) and after that just sneek your way to teh ballistas for teh clan points ( 15 points each ballista) 4 in every fort no matter what fort size.