I didn't find it overpowered. In my few games the winner has different games the most of. 4 points (in 2 players) with the multiplier maxed out will give you 20 points. But so will engine building, and you only need 4 cards for that, no need to compete with others. Or set collection could even score you 30 points if you went all in on it. Co-op maxed out at 15, but you only need 3 cards and a bit of luck.
Anyway, on average the marketing points only make up about 1/3 of the total, and typically your strongest marketing making up about 2/3 of that, so hardly game breaking.
However, the good thing about a bga implementation before the release is that they can analyse the thousands of games played, and balance it out if there's an issue, which is great.