Prior to Mop there were some items easily attainable on one faction which sold well on the other (eg pets). From what ive seen of Mop this is no longer the case. So, on your server, what are some things that sell for alot more on one faction?
You havent ben looking at MOP long then. There are always plenty of opportunities to engage in arbitrage to exploit price differentials. Why not just use UJ to se what the differences are on your server. What use does it do you if the price differentials people describe are not on your server?
Its been my experience that things were more expensive on the smaller faction, but not always. There are numerous threads on how to make gold. The other faction just becomes a possible supplier, but with the added cost of transfer. It cna be highly lucrative, but it has its own challenges such as neutral ah botsniping.
Anything you know can and will sell on faction B but can be bought on faction A for considerably cheaper than producing that item on faction B is a potential source of profit. Knowledge of your own ah is always what pays dividends, its just another version of supply and demand.