I'd like to start off by saying I really enjoy insurgency, as I've put many hours into this game. As with other niche titles in the 'Realistic FPS' genre I adore, there seem to be a collection of small issues that build to make a less than enjoyable experience over time; as the player will constantly run into these issues. Here are a few:
1. Community servers without ranking
I personally strongly dislike the matchmaking system, aside from it's use in competitive. This system makes players unable to play with the same teammates, making it more difficult to form bonds with teammates as you may never see them again unless you get lucky or add them. My main gripe is after the system removes you from the completed match, there's a good chance you will either A] get into a new match with the same map that was previously played or B] will be put into a match already in progress which tend to be half finished. This could easily be solved by having IO add their own dedicated ranked servers to the server browser until they decide on a method of implementing community ranked servers.
2. Dying shortly after objective capture and having to wait till next spawn wave
Recently, this was addressed in the coop game mode (Checkpoint) and I was surprised to see it not added to the versus mode. I understand why it wouldn't work in competitive but it sucks in the regular versus mode to have to wait upwards of 45 seconds to respawn (depending on how quickly your teammates die) if you died on the objective just after capturing it.
Here's a thread on reddit also discussing the issue
3. The respawn system
My favorite series of similar genre to insurgency was Red Orchestra and I feel Tripwire implemented a better respawn system as the player never had to wait over 30 seconds to get back into the action. This was mainly due to two things: Using a ticket system where each teams tickets represented a players ability to re spawn; and a wave based spawning system that starts counting down time to spawn once the first player had been killed. In the current system, I've experienced longer wait times to spawn due to the game waiting for a specific amount of people to be killed on my team before a countdown to new wave spawn can begin. Whereas in Red Orchestra, the system begins creating a pool of players to spawn once a player is killed and spawns them at the cost of the teams tickets. My feelings on this issue aren't concrete but I feel like there is room for improvement in this area.
4. Spawn killing
Though this is rare, I've seen this happen specifically on the maps on Crossing and Summit; there are areas a player can get into that look directly into the spawn of their enemy. For the map Crossing (When the attacking side is coming from the Hilltop Fob) it is possible for an attacking player to get behind the A objective and shoot directly into the defending spawn. For Summit (When the attacking side is coming from the usual market area) Defenders can run towards the B objective on the hill and find a specific spot inside the play area to shoot almost directly at the attackers spawn. These issues could be fixed via giving spawning players a brief 2 second period of invulnerability.
5. Workshop Support
The title speaks for itself. I'm surprised that workshop support has not yet been implemented as IO has frequently stated their love for modding and their modding roots. I know these things take time but mods are another way of adding to community longevity. Hopefully the ability for players to create their own game modes and the addition of new player made maps will help with the burn out some players are feeling.
6. Character Customization
I was personally surprised that I was unable to give my INS character a truly militant look. There are no options for having any OD green clothing or chest rigs, milsurp looking clothing or camo for insurgents.
7. Issues with gamma/brightness
On certain optics (I've had the issue with the x1.5 optic, Kobra and red dot) and with fire from molotovs, the games gamma tends to be lowered significantly where it can be hard to see. Hitting ESC and returning to the game fixes the issue but it's annoying to do in the middle of a battle. This may have something to do with the motion blur settings as I read the specific setting has HDR, eye effects and other features tied into the setting.
Those are the main things I wanted to comment on. Please give me your thoughts and feedback or mention your own criticism.