That is kinda the "idea" of the map as i see it. And i dont see it in a bad way as u say. It's just a different mentality of playing CS, once u enter vertigo (and nuke as well but nuke is already polished map). That the map is VERY small, yes. But is that rly a bad thing just because it? I dont think so. The idea of having so fast rotations, of having danger of being killed by ur back, cuz someone out-smarted u? I love that idea, of fast, intense plays. And i think this map is what it searches for. Trying to play mind-games with ur oponent, and fucking them up. Without the good old typical executes with 5 smokes, 4 mollys, 3 flashbangs, now we go in! 30s before end of round. I mean.. yeah this is CS and what makes CS be CS, but we see this so much, that its becoming stale. (cache's problem IMO, became a very VERY dull, and stale map).
That maybe in pro lvl its a flop? We dont rly know.. only several tier 5 teams played at it, which cannot be used honestly as consideration. But I have a feeling it wont be a flop, and if its broken in some aspects, Valve will tweak it up. Overpass was a hot garbage map as well in 2015? or 14 dont remember, when it first entered the pool, now here we are. (I remember very few of it, but it was VERY hated the map, even more than vertigo i would say).
Im a fan of nuke, so it also came in as a nice surprise when i saw vertigo.
And that there is no other maps in the pool? there is. But people refuse to play them. But most of them are not even interesting to play.