Hey, I hate to see requests for feedback unanswered in this forum, partly because I ask for feedback all the time.
So here is some of mine.
Interesting idea to make an arena map, we don't have many of those. Some feedback I can give you is that you should think about picking one type of architecture and mostly sticking to that. You use different wall props with different types of stones, having only one 'culture' makes it look a bit more convincing, although I get your map is more focused on the practical use of the obstacles.
I think having some cool background stuff going on, like the city, especially that building with the path on top of that hill, really gives your map some flavour. Performance is always something you should keep in mind though, and you should not use too many objects to create your backdrops, especially considering the average player won't even notice it while playing. With the pretty high walls you have, creating a backdrop which is not always visible should eat up too much performance.
I am still trying to get familiar the edit mod, and it takes a veery long time to find the objects I want to put in. That is one obstacle blocking my process.
Unless you are really going to put like a 2000 hours into scene editing, finding the right scene props will always be a bitch. Here is a tip from me though, do the mapping area by area, first think about what you want to do with the area, then go through the scene prop list once, placing every prop you even remotely think of using in some empty corner of your map. This way you can always click them, check their name and then look them up in the list. Saved me a lot of time.
Spawn 2 has an overall better defensive setup. They have an easier acess to their tower, and have more defensive obstacles to benefit themselves. However their defensive structures also have some blind sides. That's how I planned it to be at least
In my opinion it is very risky to make the spawns unequal like this, it can easily lead to one side always camping and one side always attacking or the map being unbalanced. I recommend creating strategic locations which are exactly as far away from one spawn as the other, so that the battle plays out differently every time and people have something to fight for. Mostly battle balances itself though, it is too unpredictable to really have a huge influence on it as a mapper.
Textures and ground colouring are an easy and not resource intensive way to improve the look of your map. You have a lot of one texture, getting some grass or earth in there might be nice. The key to texturing is using low weight and hardness settings and making smooth transitions and blends of textures.
After all these hardwork, I couldn't spot those. Thanks for making me noticed. Fixed now.
Spawn a horse in the scene editor and just ride around for a full 5 minutes, will make you fix 90% of the errors you couldn't see while editing.
I hope none of my feedback makes you change your whole map around or anything, you should take it as advice for future mapping, for a first map it's good. Also, get some daylight and pretty sunlight and high settings when taking screens, makes any map look a whole lot better.