StarCraft II Choices

I finally started playing StarCraft II, which is obviously an amazing game. I'm addicted to playing and loving the new units and story so far. Anyone that knows me probably also knows that the original StarCraft is my favorite game of all time.

Although, I admit I have one complaint - the choices. As an RPF fan, typically I love being offered alternate paths and having the freedom to impact the game, but this isn't really one of those cases. I hate permanently missing out on a potential upgrade just because I chose to research a different upgrade. As a strategy game, shouldn't I be given both options and allowed to strategically decide at the time which best suits me?

I'm also not a fan of how the story progresses. I don't really need several options about which mission to do next. I'd much rather KNOW which mission comes next both story-wise and difficulty-wise. Giving players the option to jump around and choose how they progress just seems to break the story up. Ideally, I'd like to have various options about how to proceed, but I want enough direction to make a decision about how to do it.

Still, I'm not done with StarCraft II so I'll reserve my judgement. And either way, I'm thoroughly enjoying the experience so far.