So i went around it and here is my feedback:
The first thing i saw was that there are no spectator cameras.
Solution: Add a few info_observer_point to your map
The next thing i noticed is that there is only one spawn exit.
Solution: Spread out your spawn room and add several doors to different areas, each main spawn must have AT LEAST 2 exits
OH GOD THIS IS JUST AWFUL, I COULD SPAWNCAMP ENEMIES ALL THE WAY FROM MY OWN SPAWN.
Solution: Add doors, props to block off these sniper sight lines
I can open the enemy's spawn door, this could lead to some serious spawncamping.
Solution: Add 2 filter_activator_tfteam entities to the map, name each one blu_filter and red_filter, then the trigger_multiple's Filter Name property should be set to your filter_activator_tfteam's name to make the door team-specific.
This vent is dark.
Solution: Add a light inside.
Thats all for now, not bad for your first map (it's so much better than my first one), i'll give you some more layout related feedback later.