Is the Gearing the best dd for team play? What are the options? I try to break down choices.
First- we need to really think about what a dd is supposed to do in Clan Battles:
Keep targets in LoS (Scout)
Kill other dd's
Kill bb's and cruisers
The Gearing has very good dpm under 6 km at 36000 HE and 42000. It can turn very well to dodge torps and incoming fire, and has good concealment.
The Grozovoi has better dpm at range due to a 950 shell velocity, so can outgun other boats at the moment of detectability (around 6km). If the Grozovoi runs (and they are the fastest of the point contesters at 39.5 knots, they can force the engagement to the range of their choice as long as both dd's keep firing and are detected.
The Z-52 has the same fire rate as the Grozovoi at a 4 second reload, but not nearly as good shell velocity. The AP is the best of the 4 dd's compared, at 3000. Where the Gearing and Grozovoi's special ability is defensive AA, the Z-52 has Hydro. That means if an enemy dd decides to try to spam inside smoke, you can push them out.
The Shimi and YueYang aren't really good point contestors due to the nature of them being torpedo boats. They both have excellent torpedoes, but the Shimi's guns really can't keep up in a close engagement, and the YueYang has deepwater torps that basically cuts it's damage potential in half when fighting other dd's.
The Gearing, Shimi, and Grozovoi are the best scouts with the lowest detectability range (7.6 km base) where as the others are slightly higher.
The Grozovoi has an advantage of speed and can escape quicker, whereas the Gearing is the slowest and may have trouble outrunning the faster dd's.
I would say the Z-52 is the weakest scout, with both low speed and higher detectability.
Kill other DDs
The Gearing's guns are good at very short range (below 6 km) and when shooting over small islands.
The Grozovoi guns are laser beams with the fastest shell velocity. Even though the dpm on paper is lower than the Gearing's, being able to hit more often and at longer ranges gives this boat a distinct advantage in a gun fight.
The Z-52 has very strong AP, and while the guns don't turn as fast as a Gearing or have the shell velocity of the Grozovoi, they are strong when shooting broadside dd targets when using AP.
The Shimi really depends on torpedo saturation to win a 1 v 1, and are just not very good at high competitive play at killing other dd's.
The Yueyang's deep water torps make it one dimensional when fighting other dd's.
Kill BBs and Cruisers
This comes down to torpedoes and fire chance.
The Gearing can spam over hills but has the lowest HE fire chance at 5%. The Gearing's torpedoes are 16k, well beyond radar and hydro range, which give it the second best real chance to do damage to larger targets.
The Grozovoi has the best HE fire chance at 8%. The torps are arguably the worst, with a 10k range and long reload.
The Z-52 has the weakest damage torps, but the fastest reload time, allowing for more area denial, but less actual kills.
The Shimi and even the YueYang are the real winners here with great torps.
The Gearing has the best smoke duration. But this is of questionable importance in Clan Battles. While smoking for a team mate allows them to shoot in cover, bb's can not take advantage of this. Cruisers can, and do appreciate smoke, and other dd's can take advantage of smoke if working in pairs. Having long duration smokes gives longer concealed time, but to be honest, if you stay in smoke more then 10 seconds at top tier gameplay, you are a torp magnet. This is why I think having long smoke is a double edged sword- sure you can stay longer, but do you really want to?
Conclusion (or TL:DR)
Though no dd is the best, some 2 dd combos become the clear winners:
Z-52 and Gearing- if your dd players are more aggressive then the Gearing combo may be the best choice. The real advantages in this grouping are the smoke duration and the ability of the Gearing to torp at 16 km (beyond the Radar/Hydro range).
Z-52 and Grozovoi- if your dd players are more cautious then the Grozovoi combo may be the best choice. If the Z-52 stays forward and smokes, the Grozovoi can better snipe at a comfortable range (9 - 10 km) which is out of the effective range of the Gearing. Late game this combo suffers as torpedo range is within radar range.
While being strong boats in their own way, the Shimi, YueYang, and Khaba are just not recommend for Clan Battles. The Shimi's lackluster guns and YueYang's deepwater torps means they can not contest caps very well, and the Khaba, while a great harasser, can not cap as well either due to the range it can be detected. Since Capping is the primary role for dd's in Clan Battles, and damage/scouting are secondary, these ships just do not do the job as well as the Gearing, Grozovoi, and Z-52.