Since it takes very little skill to use I lump it in there with the grenade launcher attachment as being for people relatively new to Halo. If you rely on this weapon in multi-player you will quickly notice you only very rarely get a kill on the best players and these are looking for you since you're using a "cheap" weapon.
I think it's perfectly fine. It has the range an effectiveness of the other CQC one-hitters, but it has to charge before use, and you can't hold the charge for long. To add to this, two fully charged shots are all you get before you have to reload. To me, it's perfectly balanced as a loadout weapon, and I agree with Big that you'll get rocked if you try to use the Boltshot an entire match vs skilled players.
I agree with bitesize. They nerved the gun *Fist PUMP* its no longer like a power weapon like it was when the game came out. Theres no more 10 feet away boltshot kills and let me go further into this. There are ways to work around the boltshot if your in that one on one situation! Maybe that's you jumping backwards for the ninja as he try's to boltshot you from behind. Maybe that's you throwing two nades to kill the guy because he was camping waiting for you to come around the corner. Or maybe you just grab the the sniper blame him in the face right before he can get the shot off. There's ways to work around it and its not overpowered anymore in my opinion.
It's still overpowered and should be removed from Loadouts. You are essentially starting with a shotgun. Even nerfed it has the range of the UNSC shotgun. Add this with Camo (which also should be removed) and its a camping mess.
Honestly, I have mixed emotions about it. I find it a lot of fun to use on people (cheap and a horrible thing to do, I know) but I hate when people do it to me. I think it's fine to use, even though I suck with it, and if nerfing it like crazy helps you get points and win games, then by all means go for it. However, it is a little bit too close to the mauler. I don't see why they didn't just bring that back and not give the boltshot it's shotgun powers at all. It would've given the game a lot more challenge.