Thank you for this feedback! We've mentioned the Gun Game Mode in our latest community update:
In regards to new arcade modes, team-based King of the Hill and Domination inspired modes were highly rated (receiving approximately 24% of the vote each), as well as a free for all Gun Game mode (19%). Considering the relative similarity between the team-based King of the Hill and Domination inspired modes, we are unlikely to pursue both. To determine which one we will pursue, we will poll everyone once again to hopefully get a more clear winner between the two.
You can also learn more here: https://forums.focus-home.com/topic/38719/insurgency-sandstorm-community-feedback-results/