I don't see the problem honestly. None of you have ever played world of tanks, it seems. There are a lot of tanks for sale in that game that are ~$50, and none of them are significantly better than the F2P tanks. Here's how I look at it, they've already stated that they'll constantly stream in new content, and that much of it will be free. I assume later down the line they'll have large expansions that cost money, but for now they've already confirmed that small expansions, like the beach bum pack, will be free. Obviously they intend to support this long term, so they need to make income from somewhere to fund it. They could have gone the subscription fee route, but IMO, that would be infinitely worse. Instead they seem to be adopting more of a guild wars model and charging a flat fee for the game, giving out most content for free, but allowing micro-transactions that give players a boost, but certainly won't make them overpowered. I don't know about everyone else here, but even before I started making substantial money in SP, I quickly amassed a more than satisfactory arsenal of weapons just from playing the game. I just use my wealth for ridiculous things now. It doesn't make me a better player.
What I'm more worried about, honestly, is the leveling system. The reason I stopped playing max payne's online mode after a few days was because it simply felt like I wasn't making meaningful progress. After taking a day to get adjusted to how it worked, I carried my team to victory 99% of the time, and could do so pretty much with any weapon I had unlocked, but it just took way to long to level up weapons and unlock new ones that I just got totally bored of running the same to pistols over and over and going on tears. It shouldn't be like call of duty where you can sneeze on an enemy and gain five levels, but at the same time I hope they reduced the XP required to level up. Otherwise I could see them selling XP boosters for real money, and that would bother me.