Yes. You can use a Sony. The EVF has drawbacks and benefits. If you do a lot of macro, it shouldn't be a problem, since many macro photographers don't use the OVF anyway. If you're using a bellows lens, you may run into some trouble due to dimming - but I doubt it, from my experience the OVF is very difficult to use at long extensions factors, more so than live view, refraction becomes a larger issue.
Sony has not really ever made a "professional" body. Their market was never intended to compete with the D4 or 1D. Sony is very capable of producing a camera in this range, and there is a rumor saying that it will. But that hasn't been Sony's target market as of yet. This doesn't mean that Sony's current cameras are incapable, any more than Nikon and Canon's "prosumer" and "consumer" models aren't: they are what they are. Very frequently lower end bodies have better specifications on paper that appeal to everyone else who doesn't necessarily need the features which the D4 or 1D offer. These cameras naturally have advantages, but not necessarily for all shooters.
But yes. There is nothing inherently inferior about Sony's technology. You have pretty much all the lenses that you'd need, none of which are terribly bad from what I can tell. You also have Minolta a-lenses, and a good number of Sony lenses are just Minolta lenses with Sony's name on them. Having loads of old moldy lenses to choose from is fun if you're a collector, but is hardly a real advantage.