There are four I really hate with a passion and you only get three vetoes. For one, there is the white tile map which lags my computer for some reason (no idea why). The next one which is terrible is Old Sun Temple. This map is enormous and makes it impossible for terran to finish off a protoss or zerg due to their mobility issues. Zerg can remote expand all over the map and there is nothing terran can do about it. Old Sun Temple is just a giant terrible map. Then there is the cross spawning map (forget the name) which is terrible because it is really hard to shut down remote expansions as terran. Finally, Blackrock is extremely annoying because of its size and the unit pathing splits up your units half the time and your slow terran units get easily picked off as you try and reinforce an attack. Also, the enormous main base makes it easy for zerg to defend against any attacking air units, but impossible for terran to put up any static base in an efficient way to stop drops or nydus canals. I think I saw a game where Maru essentially just turtled and made literally several dozen turrets to prevent getting backdoored on that map. Terrible, terrible map. Washout and the rain map are not terrible but not great either. The purple map is not my favorite because of all of the obstructions, but it has the most classical base setup and not natural expansions that make it easy for roaches or stalkers to pick off your workers with ease (i.e. no good choke point).
All in all, these are the worst maps I can remember for SC2. Couple that with the insane balance and gameplay changes in 5.0.16 and the lack of a patch to fix glaring imbalances makes it seem pretty obvious whoever is in charge is intentionally trying to deep six SC2.
I mean if we are going to be objective about this, more than half of high level ladder players are zerg with the rest divided up by protoss, random, and terran in about equal amounts right now. I suspect the high level terran and protoss players are mostly inactive right now in the hopes a patch will fix this so literally most players have quit who are not playing zerg (or so it seems). I have heard reports that a permanent 10% loss of long-time players has been the result of this patch so in addition to these god awful maps, why is there no patch to fix the glaring larva imbalances (the hotfix patch did next to nothing)?
Also again with the maps, I remember uThermal saying in a video where is was in a PTR tournament that Blackrock was a terrrrrrrrrrible map and for some reason Blizzard included it anyways. I mean aesthetically it is cool, but functionally a god awful map for SC2 for half a dozen reasons.