Started playing almost a week ago. Here are some thoughts -
HUD - All and all I think the HUD and the customization available. The option for numerical health would be nice.
Movement - It seems a little off. Left to right strafing while sprinting would be nice to speed things up a little bit and try to add another layer to skilled movement, which at the moment is kind of bland. You should be able to jump on more things and do more “stuff”. While fighting, I would love to be able to sprint & shoot. Failing that, I would at least be able to sprint while reloading and sprint while using abilities.
ROF/Damage - I am not sure on the technical specs of how much damage x gun does to x part of the body. Maybe a lower ROF would help to extend firefights a little, offering a little more control when encountering multiple enemies and not having ammo piss away too fast. I am new to the game so I am not sure where these settings came from, or what direction everyone thinks they should go in. TTK is kind of short. Maybe a lower rof would help with that.
Spawning - The old formula worked well and I would love it to be implemented/tested in Dirty Bomb. Having a spawn timer next to the mission time would be a great, appropriate (“30s”) defensive spawns that penalize players who choose to be aggressive at the wrong time. Right now it feels chaotic and unorganized. There are way too many random pushes from defenders because there is no penalty for doing it. Spawn timers and reinforcement timers would be a great addition.
Waterloo - another route(s) for the first phase would be a welcome change. Samurai had some nice ideas in his thread
- the first objective feels like trying to plant at the old city wall on Oasis. So much spam on the wall from above 
- plant times vS reinforcement times might need to be adjusted (on all maps)
London Bridge - My least favorite map at the moment. Up until the EV reaches the stage where you escort/carry 2 objectives feels off. Too many routes, too many angles, too many ways to get shot in the back, flanked, etc… I think the first part of the map is too vertical. A catwalk on top of a bridge on top of a road. Sure, goldrush was like it, but it just doesn’t feel right.
The most exciting stage of the map, the doc carry, is the shortest. If the attackers make it to outside with the docs there is little hope to prevent them from securing, as the EV is parked immediately in front of the entrance, and there is plenty of cover. In “Goldrush”, trying to escape the bank courtyard and go short/long was the most exciting part of the map. It would be nice if some of these doc carry maps captured that excitement. I think this stage of London Bridge could be improved upon.
Camden - My favorite map at the moment. Love the layout, and the love how the art/texturing has progressed since I first saw it in the MS16 video. Lots of good battles around each phase of each objective. The second objective is normally a painful grind from my experience, but fun nonetheless. On the last stage D are easily camped.
Player base - It is extremely small. I understand it is an alpha, but currently the only time for people in North America to play is on Euro servers in the afternoon (their evening). This is problematic as most people in NA are working at this time (or just getting home from work), only leaving weekend afternoons to get some games in with a full, or mostly full server. Inviting some of the elite crowd in might improve the situation.
Hit Reg - it’s wierd. You hear so many shots land but there he is, still standing. Still need to test this out further if a second person ever connects to a US server…
The airstrike - I pretty much echo what pulley said in this (http://forums.warchest.com/showthread.php/35863-New-old-Airstrike-Question) thread. It is pretty much useless at the moment due to what seems to be an error with explosions compared to marker placement. I remember an older vid where it appeared to have more bombs spread out over a bigger area. How did the testing of that go? At the moment it is pretty much useless for trying to gain a heavily defended area, or hold off a large rush. I wish the can itself was “heavier”, so it didn’t bounce around like a tennis ball when you throw it. It has made some strange deflections/bounces for me
Game modes - I hope you include some more game modes (CTF and/or base race)
Plant Animation - I really wish we could get away from being stuck in a plant animation. Giving the engineer the option of throwing down some c4 and moving around to keep tapping it with his pliers might increase successful plants. As it stands if he hears someone coming he doesn’t really have an option. It would be great if they allowed free planting anywhere. Being able to drop c4 anywhere and arm anywhere would be an improvement.
Doc Carry Objectives - I pretty much echo what other people are saying. This shoudl be the most exciting part of the map but it’s current setup is flawed. The EV sitting right outside the door doesn’t allow much chance for the defenders to return (on london bridge and white chapel). I also wish it was touch and go, and no “loading” of the objective. It’ll bring more excitement to those quick grabs or clutch returns.
Objective Placement - Radar was my favorite map in ET. I loved the whole east/west defence and rotating back and forth, and the dynamic the forward command post added. There is none of that same feeling in Dirty Domb. Objectives are placed within 10 feet of one another, making it one big lemming rush with little or no tact involved. Provide more routes and space out the objectives a little, forcing the “D” and "O’ to make some choices. As it is now, it’s spawn and mindlessly sprint to the objective(s) 
Misc stuff - Pretty sure this is known, but you can’t go near the EV without getting stuck to it.
- need more forward spawns. It would throw in an extra side objective to fight over. Flag fights on ice & command post fights on radar were always exciting.
- the covie needs some love. When adding some extra routes make them a covert door which he can sneak through or blow
I’ll add in more for the other maps + suggestions for improvements later :>

) with the spawn timer. Maybe some talented comp. mappers can help here. Maybe some of the ETQW Map Designers at SD can give some feedback because overall they did a good job regarding spawn wave timing.
)