Nice job phi
from walking around the map I have some things I want to discuss but I definitely think the map has a lot of potential, so grats, it's not often I can say that about an early alpha build map.
starting at mid
http://i.imgur.com/OSQt84W.jpg
Mid looks REALLY good from a first glance.
It obviously takes some inspiration from metalworks, yukon, and gullywash which I think is a good mix
http://imgur.com/wBr8Rr3.jpg
The low ground area seems like a really good area to push 6 into through which is cool but I don't think that will really be possible because there is another major entrance on the other side but I think it will still result in some pretty good 4 or 5 man dry/uber/number pushes nonetheless.
I think mids will generally play out to teams taking control of one side or fighting over one side similar to gullywash or process. It looks like every class has opportunities to control the space but it does seem to be scout favored for how open it is
http://i.imgur.com/xx8n3Mw.jpg
For this ramp area I'd be interested to see how the mid would play out with and without it because I think by removing it, you emphasize highground positioning a lot more in terms of medic and scouts because you can't quickly climb up
http://i.imgur.com/tSDlXYq.jpg
This room seems largely useless to me as I think it would be better served by adding a pack and small ramp up to the right outside on mid and I think the area you can push through from it is not really necessary.
http://i.imgur.com/N5cl85C.jpg
So the highground transition area makes the lowground transition largely irrelevant to me because the same positioning guards against both and I don't really think both are necessary because there is another good solid entrance to push through on the opposite side that needs a different set of positioning to hold properly w/o uber for most of the classes. I think it would be worth removing the house area and instead making the lowground transition area less low-ground and make it a solid choke (possibly similar to how process's mid->2nd choke is set up) would probably make the entrance a lot stronger and would cut down on the size of the map which I currently think is probably it's biggest problem(seriously everything is REALLY far away, I think mid and last could possibly be made smaller but I def think you should test this first, because larger map sizes tend to emphasize scouts and in a way snipers)
http://i.imgur.com/H9pwzEr.jpg
This area seems really awkward, it might be better to make a clearly defined upper / lower level which would also make pushing into 2nd from this area a lot easier because it would be harder to read the push
http://i.imgur.com/7UFE7VO.jpg
I think put a wall there instead of a railing to break up lobby a bit and also that sniper sight line (especially when defending) is ridiculous
other than that I think lobby seems fine, obviously given the distance from last to second and the size of last the point has to be pretty slow capping
This last certainly feels very large although I would say it's roughly similar in size to granary or process although the chokes are much bigger
The last seems very coldfront-esque which I think is fine given how it's laid out
I certainly want to play this map a few times just to see what pops out but I want to prompt some discussion especially about the maps size, there seems to be some dead/unimportant area which is a bit strange and the map seems a bit stretched (especially mid)