I mean let’s see what are missing first.
The US: BW ships, coastals
As of the ship I suppose the USS Gyatt in the DDG-1 configuration. Given how the bravy has limited significance in the game yet, the Gyatt won’t make much of a difference. Similar to the bravy it is armed with a twin terrier launcher, BR 5.0.
The coastal can be the monitor gunboat in a howitzer configuration. We are yet to see gunboats that has a silly sized HE launcher.
Germany: helicopters, BW ships
If we keep thinking about Poland, then sure, maybe the Mi-24W from Poland can work. However it is just simply a Mi-24V. Alternatively, the H-145M that was recently introduced into service could have a try.
Although there werent any squadron battleships yet, their existence will only be a question of when. Looking at the current fleet, perhaps the Deutschland or other ships of her class.
USSR/Russia: helicopters, BW ships
I had long heard for the Mi-24VP as a squadron vehicle for the USSR. In all fairness, it does not sound too bad.
As of bluewater ships the Soviets do the best at is 5.0. The Kiev could be a good choice since it is better than ships like the tashkent.
Britain: helicopters, coastals
By any standards the South African SuperHind or XTP-1 helicopters are a good choice. Alternatively, wildcats armed with martlet missiles to enhance the uniqueness of British helicopters mounting dual-purpose missiles.
Monitors are yet to be a concept in warthunder, which although sounds silly in the game meta, but the M15 class monitors can definitly have a go in warthunder.
Japan: tanks, helicopters, aircrafts, coastals
The type 90 regimental command tanks passed to devs last year seems like a good choice. But once again, it is good both as a premium and as a squadron tank.
The helicopter can be the UH-1 Ninja, albeit it cannot do anything other than acting as an AA. There is also the options for an OH-6D armed with TOW missiles similar to the lahtut.
For the aircraft perhaps the T-2 CCV. Alternatively, planes such as the Ki-84R/Ki-84N can fill out the problem of Japanese fighters being out-energied in superprop regions.
For the coastal, there are things like the hayabusa class, which was fitted with ASMs and most importantly an OTO melera gun, the standard of any high-tier western coastal ships.
China: helicopters, aircrafts
The Z-10 prototype featuring a longer tail and different exaust designs can be the basis of a Chinese squadron helicopter. Alternatively the AH-1W from Taiwan is also a good choice as China severely lacks helicopters that have competitive A2G missiles.
As of the aircraft the JL-9 Shanying(Mountain eagle) sounds like a good choice, beginner friendly(as it is quite literally a trainer), armed with a basic 23mm pewpew cannon(meh), two PL-8/9 missiles and 5 pylons with a decent amount of bombs and rockets. This would be then, very similar to the Sea Harrier FRS.1(E).
Italy: tanks, helicopters, aircrafts, BW ships, coastals
The most heavily suggested squadron tank for Italy is the Ariete HITFACT Mk.2. Honestly this isnt a bad choice, so I will support this idea as well.
As of helicopters, the A109 I-DVCM sounds like a good idea. I would also perhaps think about the Romanian IAR 330 puma, since it is uniquely armed with Romania-made Soviet/Russian rockets. Weapons such as the malyutka were trialed and there are even SPIKE-armed versions.
For aircrafts the ideal choice could be the M-346 Master. The M-346/Yak-130 offers a balanced high-tier CAS for Italy, Russia and Israel. The base version can be allocated as a squadron and the M-346FA below the AMX in the TT. Brazilian AMX is also highly suggested and I believe that Brazil definitely needs some appearnce in the game considering how big their military is.
As of bluewater ship, I would pull out the Giuseppe Garibaldi, a cruiser that survived pass the war, and in the 1960 config - armed with eight OTO-melera guns and terrier missiles(and polaris), which can be an interesting ship at BRs such as 4.7 with its extremely deadly guns against destroyers but weak against anything larger, assisted by the terrier missiles.
For the coastal ship, the minerva class can be a good choice. Their arsenal of OTO-melera 76mm, KBA 25mm guns and albatros missiles can be a very good contender to ships such as the SKR-7.
France: tanks, helicopters, aircrafts, BW ships
The AMX-10 RCR is probably the first idea off the head. Stabilizers meant a lot for France, and hence that is why it could be a good idea.
The IAR-330 PUMA that was previously mentionec can also be something the French receives. Alternatively the Tiger ARH under Australian service also seems quite good for a squadron vehicle - armed with APKWS and hydra rockets being the notable difference.
There are multiple suggested aircrafts on this forum such as the Mirage IIING, or the Mirage F1-M53, which all presented themselves as a possible candidate for squadron aircrafts. I would also suppose the Super Etendard without guns but armed with AS-30Ls and a DAMOCLES TGTP, or even an exocet-mounted Super Etendard from the Argentinian navy(THE BRITS HATE HIM!).
The De Grasse in the post-war refit is the ultimate war thunder cruiser. Armed with 8 twin 5-in batteries and 10 twin 57mm bofors batteries, she is almost but certain able to melt destroyers at an astounishingly pace. Although in all fairness the De Grasse is probably better as a TT ship.
Sweden: helicopters, aircrafts
I literally found not a single candidate for a Swedish helicopter. HKP 14, the NH90 NHF arent mounted with proper AGMs in the current stage, Mi-8 and HH-10 in Finland saw no additional weapons mounted, neither does the Danish fennecs.
As of the planes, I suppose a Finnish MiG-29 9.13 isnt going to make anyone made. The Finnish air force has been trying to acquire the MiG-29 all the way until 1988 where the collapse of the USSR did terminate such plans and they switched to the F/A-18Cs, and there are allegedly Finnish pilots already training on fulcrums. They could have an interesting loadout where they only have access to base R-27R/Ts but also has R-73Es to play with.
Israel: helicopters, aircrafts
The lahtut has the potential to be armed with domestic MAPATS missiles. Alternatively being a big wargame nerd(and Israel bully player) I must put forward the yas’ur(CH-53 sea stallion) armed with the nimrod AGM. It has rediculous range for a helicopter mounted AGM.
There are also plenty of planes possible as squadron aircrafts. I would put forward the MiG-21-2000, since they were upgrade proposals from IAI. The elbit proposal, the LanceR, was fitted into service and would be less fitting for Israel.
