A good start. Still there's room for improvement and i guess you intend to improve since it's labled alpha.
I've attached a screenshot of the map with mat_leafvis 3 active.
As you can see, there are still a lot more visleafs then neccessary.
You should turn all the arches and small shapes into func_detail to avoid this.
Also i'd recomend you to either downsize or replace some of the textures that look blurry.
Make sure to use scales like 0.5, 0.25 or 0.125 for them to get sharp results.
Since the mapping is rather basic, you need to have sharp textures and good lighting to make the map awesome.
Speaking of lighting, i recomend you to increase lightmap resolution for sharper shadows and make a better use of lighting inside the "towers".
Give each of them a unique light color or something else to make them distinctable.
Think of fire, water, light and life.
In other words make one of them with blue trims, water maybe even a waterfall into that pit and blue light, the second one red trim with red light and fire in the pit, the third one with green trim and plants inside (maybe remove the roof, or part of it and have some water floating over from the water temple) and the forth one beeing dedicated to light could have a small opening in the roof too and a ray of light hitting a big crystal in the room which illuminates the whole room.
Last but not least, i don't see a reason to restrict the map to DM and Arsenal.
Just place all the teamspawns in oposite towers, place gameplay tokens in the other towers and it should work.
MWGG is also possible, maybe restrict GG spawning to the weapon spawn in the center.
LtK is always possible, CtF and LD should be too.
