Allow me to add a few points so there can be even more fine tuning.
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LAYOUT
The distance between the starting positions of the two players is a little (EDIT) shorter than it is on other Blizzards maps. A peon needs only 46 seconds to walk from town hall to town hall, but on most 1v1 maps he needs 52 to 60 seconds. That may not seem like a big difference but a high level player will notice and it will have an effect on how games are played. This problem could be addressed by pushing the base a little further to the corner of the map. You have a lot of room there.
You can build a burrow behind the bottom gold mine, but not behind the top gold mine. I would make it equal.
The paths in shallow water behind the expo are a bit narrow. Since you have a lot of room there I would recommend to widen them a little. The map will still have plenty of choke points - perhaps even too many.
Some spots allow for a small unit (acolyte scouting) to hide from a bigger one (hero chasing him down):
It has been argued that the Sunken Ruins merc camp might be imbalanced,
see thread here.
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CREEPS
The camps guarding the expo are placed too aggressively, they should be closer to the gold mine. Same goes for the creep camp guarding the goblin merchant and some others.
The lvl 5 murloc camp next to the base drops two items, one lvl 1 perm and one lvl 1 p-up. I would have it drop only one of them.
The red camp in the corner is lvl 21, which usually warrants for a lvl 5 item, but instead it drops a lvl 4 plus a lvl 3. That is highly unusual and people will probably not like it. For example, you may not have the item slots available for two items and would prefer one strong item instead. Also, access to that camp is very narrow, your opponent could practically seal you in.
The lvl 13 camp at the merc camp drops a lvl 3 PLUS a powerup. That's too much, I would make it a lvl 2 item.
Contrary to that, the lvl 16 murloc camp only drops a lvl 2 item, which is not good enough, even if the additional powerup is a lvl 2.
The Revenants at the lab drop nothing.
What I'm missing is another green camp. The total levels are: 3, 5, 9, 11, ... You only get two tiny green camps, and for the next bigger spot you need to kill the relatively strong skeletons which are close to your enemy. On a side note, the skeletons have no anti-air, and neither do those at the merc camp and the revenants at the lab:
NE might dislike this map because you cannot farm creep camps well with an AoW. I guess the giant sea hunters at the shop are an option, but you need to build quite a bit away from them. Have a NE player give his opinion on that.
You forgot to place critters I think, at least I didn't see any.
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DESIGN
I'd probably put grass or thick grass under all palm trees, but it's a matter of taste.
Another thing are those ugly little 2D rocks which you can hide by lowering the doodad:
Blizzard didn't do good job there.
I've got to add that I've never been a huge fan of the Sunken Ruins tileset in itself. However, your mixture of terrain is good and so are most of the doodads that you've placed. It may not mind-blowing but it doesn't need to be that anyway.
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With a few fixes, this will be very playable map.