First my credentials.
I've played over 1000 games of Dominion and when we could track rating I had about 2050 when Jabebot was around and 1950 when lolmatches finally stopped recording them. I play Dominion almost exclusively when I play solo and I try and convince my friends to play Dominion. I just wanted to throw that out there so people realize I'm not speaking without some experience since I don't post on these boards all that much.
I'm really enjoying the Blackfire torch. It breaths new life into characters like fizz, teemo, brand. There seems to be a lot of complaining about this item but I think it's a little over the top. It certainly shakes up the meta, and I think that is what people are reacting to more then anything else, but personally I am OK with that.
I wanted to check this item out for myself. I've been playing one of my mains (Fizz) and I recently bought Teemo. Blackfire torch doesn't make AP casters overpowered. You will not see a team of 4-5 AP casters with this item and win. You could have a full team of bruisers, say Jax, Jayce, Darius, Pantheon. I bet on a team like that more then a full team of AP any day. Bruisers were king and although the playing field seems a little more level now, I still think a bruiser character still holds the edge.
That being said I think that it is too powerful on tanky characters. Personally I think the dot should scale with AP, which has been mentioned in other threads.I know there are nerfs incoming for the BFT when S3 comes (as well as other items) and I am hopeful that the riot team will do good by dominion.