For dominating what would change?
That build is for DOMINATING.
I have read that putting some points into Mercantile is a must.
No, not really. It's only a must if you absolutely want to buy best jet skis with best parts, buy a lot of super steel plates or find slightly better components before DC. If you're content with the aegis patroller (which is really good), 6-12 plates and +/- 150 components, you will be fine without it.
The 25% sell price hurts a little bit early on, but you quickly learn what items to take to make the most out of your loot and acummulate money from quest rewards. There's a lot of money to be earned at the Black Sea, and by a lot I really mean a lot.