You don't know many top players do you? They can and have switched from one day to the other; adaptation occurs over a few games once mastery over one race has been achieved. It's all in the micro, knowing how units work, and knowing the build orders in advance. You give yourself and the top players too little credit, barring that you just may plain suck at RTS games or that one in specific. It takes one game to figure out what builds what, it takes another game to get use to the hot keys, and it takes one more game for an overall adjustment. So three at worst/best. Also drop ship microing is pretty standard across all the races, so your analogy falls apart yet again.
There is very little difference in the execution of a lurker user , tank user, and a reaver user.
Posting BS like this makes it hard to even read the rest of your posts. Adapting (meaning playing another race just as good as your original race) in 3 games in WC2 or maybe the newest C&C game might be possible for a top player. In WC3 (and probably Sins) it will certainly take some more games and for most StarCraft top players it just won't be possible to be as good at playing a different race. There are a few very good (non-korean) players who don't have a real main-race, but pick their race depending on the opponent's race, but that's not really changing their race and they might still "suck" in some other match-ups. As an example, showing how hard switching races is, early last year the best starcraft player in the world (at the time) announced he would play Terran against Zergs from then on instead of his normal zerg-only. Now he didn't decide this from one day to the other, he already played Terran in a lot of casual games before, he had years of experience in the TvZ match-up from the other side and and he had a few weeks time to train his Terran in a professional environment. So how long did his change to Terran last in tourney games ?
less than 15 minutes ! That's how long it took a "mediocre" (still top50 in the world IMO

) zerg to destroy him. After that single game he went back to playing zerg-only in tourneys.
Oh, have you actually played SC at all ? Using a Lurker like a Tank or a Reaver like a Lurk ?! 8[
I also think your post broke the thread for FireFox =/
Ah well, back to Sins:
No, the races are not the same.
Yes, the races are similar.
Yes, it's better than in beta 4.
No, I'm still not happy

TEC vs the Advent is fine. The differences in style and approach to the game are apparent immediately. TEC look bulky, they get good civics techs early, their ships are more solid etc. Advent are fragile, use more advanced weapons (beams everywhere), they get their prototypes earlier, they clearly benefit from culture and they usually have an advantage in numbers.
Now come the Vasari: Up until the lategame with level 6 caps, phase stabilizers etc they just aren't really distinct. Sure they get trade and culture later, they get a few different economics techs and stuff, but there's nothing which makes them stand out until the lategame.