Tl;dr: The mode is a welcome change of pace and plays much more like the original Destiny 1 from the Console era than Destiny 2 ever did. But it still has potential to utilize as a game mode. Overall I had in that mode the most fun in 6v6 since the old days of D1.
[b]Here a few thoughts on the game mode...[/b]
1. The game mode features a "progression bar" that increases from Assists, Kills and Objective contribution for granting you special ammo. However the game mode TOTALLY SHOULD let players be able to pick between 2 rewards for this counter at the start of the match. Option A should be Special ammo, but slow ability regeneration. Option B should be no Special ammo the entire match, but regular ability regeneration for a certain duration after reaching the maximum of the meter (which gets lost on death of course). That way players can more determine on their own what play style they want to follow while still restricting themselves in certain combat situations a lot.
2. The Progression bar contribution is right now 2 points (or around 20%) from a single kill or objective contribution (for example, a Zone capture). Percentage-based bonus for assists (as far as I have seen). In my opinion the Objective contribution should actually grant 3 points (or around 33%) so the objective play is much more encouraged. I have seen a few players still tingling around like lost sheeps in the game mode, ignoring the capture points most of the time. Encourage them more, Bungie!
3. 100 points Score Limit but a time limit of around 12 Minutes is too low to feel fully fledged out. Increase the point score to 150 like regular control, so teams have actually a better chance to catch up to the opposing team during that match time.
4. The default slow ability regeneration appears to be a tiny bit too strong at the moment. For the most part abilities like grenades and melee are fine, due to weapons (and perks) existing to support the regeneration (for instance, Pugilist, Demolitionist, Classy Contender, Travelers Chosen, etc). Super abilities on the other hand in that mode are maybe appearing 0-3 (across the entire lobby) at best in the last 10 kills before a team wins. Players like me that still run Intellect 100 and do make kills takes it almost the entire match just to get even close to 1 full super. Maybe tune it up a tiny bit so it still plays like Destiny and less like a Movement glorified Halo Arena Shooter ;)
Other than that, no further critic points. The slow pace makes even the worst maps actually be good for 6v6 because people play much more cautious and more as a team as they used to play during D2 Vanilla, which the most maps were actually designed for. Not once so far have I encountered a dead spawn (when someone spawns in enemy line of sight).