I think this would break the game mechanic a bit. Imagine someone who sees the CP on the third screenshot and wants to reach it.
While trying to go underwater, he gets killed by a demoman's sticky. He most likely will accuse the map design for his death, since there wasn't so much chance for him to dodge this attack, because he was unmobilized while under water.
The fourth shot reminds me of gullywash with the central cp being only accessible by demoman or soldier who can reach higher ground. This is really a bad idea, since every non-soldier/demoman/*class-who-can-reach-this-area* will hate you or the map for that.
There also has been a good reason for the gullywash's author to change that fact to a normal cp some releases later.
Long story short, keep in mind, that people want to fight player vs. player and not player vs. environment. The more control a player has over his movement and mobility, the more a skilled player will like the map.
And if these "special" gameplay elements are what makes the map special, I'd strongly suggest to re-think your concept.
Well i created gullywash, and the middle cp hole is only accessible for demoman, soldiers or scouts, the sides are accessible to anyone.
Now making a map interesting is using the enviroment, not player vs player, nobody really cares about deathmatch that much. Using the enviroment and it's variables to your and your teams advantage makes for a lot more interesting games.
Anyway like i said it's first alpha I'd first like to see some games played before i state my opinion and so should you.
Overall, interesting design, but I agree with others, you shouldn't build a map player vs environment, if you want to do that, try with a single player game like half life or portal. Multilayer games are meant to be player vs player. Maybe on the point in the fourth screenshot you could put a ramp or a bridge or something still giving an advantage to soldiers and demomen, but still allowing other, less skilled players with other classes who may not be able to rocket jump or sticky bomb that well, to get up there as well. Apart from that, the map looks pretty good, maybe a few to long a sightlines except I like your use of ramps as cover, so overall, good job, and we'll have to see how it plays out.
EDIT: After the play test today, and after much confusion, I finally realised how the middle point worked, sorry for that, but you probably should make it a bit more obvious
I took me about 15 minutes to realise the where the middle point was >.>
I think thay you should make it more obviouly point by putting hazerd strips around the cap area and maybe adding another hole in the cliff from the side people walk in from so they can plianly see the point.
nine: valve isn't doing trading
nine: they made crafting
nine: plain and simple