Even after the nerf to dark cover travel speed and the utility cost increase, Omen continues to be the primary smoker/controller for the team. His usage in Pro tournaments and ranked gameplay is high even when Brimstone was significantly buffed as I feel omens utility is perfectly augmented as to what a controller should do.

Let's talk through his abilities and how they help the team and himself

1. Shrouded Step :

The outplay potential with this ability is known to all but even if you aren't an aggressive omen who uses it for flashy plays, it's an amazing teleport to get out of a tough situation like a brim/breach ult. It also allows you to get a good position in crunch situations. Combining paranoia with it can also confuse the enemy and create panic

2. Paranoia :

People felt the cost increase was unfair but truth be told, omens utility was too cheap and paranoia is certainly a great ability. It covers a huge area and can either push out attackers who enter a choke or create space while attacking. It's large span allows omen players to flash from key points of the map even when they cannot be there so the teammates can use it for their advantage.

3. Dark Cover :

Omen smokes, the primary reason he is the best controller. While brimstones smokes last longer, omens smoke charges regenerate the longer he stays alive which means the better you are at playing omen and keeping your calm .. the more support you can give to your team by providing smoke covers.

4. From the Shadows (Ultimate) :

The huge distance teleport, allows him to get out of situations or teleport to an alternative site quicker for planting spike as the team rotates. Players in higher Elo majorly use it to gather information as to where attackers are present at a certain point of time. Defender omens can also teleport behind strategic places in attacker side to ambush them.

Sorry for the long post but I always wanted to point out why omen is such a stable character even after the changes and can be played by any Elo player with a little bit of game sense and understanding.