@Codifie All Great points, the only thing I would add is if a publisher is willing to port to unity for free, then there's likely a catch.
Agreed. It will definitely be a negotiation, some give and take, if you require the publisher to port for you. But, people need to take into account that if they can't learn the industry standard, they will need to compromise. Keep in mind, guys using the industry standard today are grossing $80,000 to $100,000+ a year if they are in fact doing as a career, and that number does not include if they are also moonlighting per se from their real job and creating games on their own or contracting their abilities out to others. A valid choice for those who can not port their game would be to check out Fiver or some other contract out service and hire someone to port for them. Of course this will have a dollar amount attached to it, but you can sometimes find someone at a very reasonable rate. User going this route need prepared, if it took you 100 hours to make the game, it is going to probably take just as long to port it, at least. So when you budget, plan for this, but again, you can find sites with reasonable contractors that can easily port your work to the industry standard and will many times add anything extra you may need.
Another option is to learn from this and decide to not go with a pub. If your game hits 100k downloads, made with BB, keep updating it and make more games. To some people, that’s a better path because you don’t have to meet a publishers requirements. It may be less money out the gate but if you use some of that money on ads etc, you could be making big money by yourself and leave out the publisher taking their cut.