Glad you will be taking a look to some non-UC amphibious MS (looking forward to the DTM-7000 Daughtseat/DTM-7200 Daughtseat III episode)! But before anything else, let me remind you that the MSM-03 Gogg ALSO has phonon masers, on both sides of its head, though only the earliest specs mentioned them. You do can see them in action in the OG TV series. I'm even inclined to think that the MSM-06 Jurick, which is heavily based on the Gogg, also has them, again as the two gaps on both sides of its head. As a minor detail, while CE doesn't have mega particle weapons, we are told in UC that such weapons have 4 times the output of a laser weapon, and phonon masers are considered the sound equivalent of laser weapons, so I generally assumed that therefore phonon masers are much weaker than mega particle weapons, hence why Zeon didn't use them that much. On the plus side, they also likely require much less power, so no need for the Gogg's much water ballast system, heavy generator and apparently also heavy beam weapon (said to be an earlier version of the one later seen on the Zeong). Back to the Goohn, I always considered it as the CE version of the Gogg, being more suited for underwater combat than fighting on the ground. The Zno would then be the Z'gok of CE, being more lightly armed, but having better ground mobility. Seed Destiny would later add the Ash which more greatly resembled the Z'gok, though evidently was far more heavily armed and I can't remember it moving particularly better than a Zno. Also, I guess the Zno also looks a bit more like a more upright standing Hygogg. Anyway, the Goohn's arm mounted missile launchers are a particularly great choice here, since the phonon masers suffers from the same problem as the Gogg's torso weapons, needing the whole MS to turn to aim them. And seeing how much better armed the Zno is compared to the Gogg, an the inclusion of arm-mounted weapons, I can't help but think of the Goohn as a Gogg & Hydro/Aqua (MSM-02) hybrid. In fact leaving overall shape aside, I think the Hydro/Aqua and Goohn have more in common, with them having weapons (of different types though) on pretty much the same locations: beam weapons that fire forward on both sides of the head, checked, forearm-mounted weapon pods, checked, shoulder mounted weapons that fire forward in causing mode, checked, backpack weapons that can only fire in causing mode (otherwise firing backwards), checked! Lastly, both have hands with no immediate apparent use... or do they? I can think of one particular scenario where they might have been used, at least in the case of the Goohn: during the attack on Panama, ZAFT deploys 5 EMP weapons, that require a MS that can both manually assemble it on site and then introduce code with a MS sized numerical panel. While the later sounds quite impractical, perhaps such system is more common among ZAFT equipment than we are shown, thus making the Goohn's hands a necessity to operate such equipment. Plus, we are only shown one group of Ginns preparing one of the aforementioned EMP weapons, for all we know, one of the other 4 could have been assembled and activated with a Goohn, which might have been hilarious to watch as it clumsily puts the device together and then its forearm missile launcher gets in the way when trying to input the activation code! Lastly, I must say I'm a bit disappointed that for the size % weight comparisons of the Goohn & Gogg, you used Gundams rather than their faction's mainstay MS, the Ginn & Zaku respectively. I don't think we can even properly compare the RX-78-2 to the Strike, starting for whether we should compare it to the vanilla Strike or Aile Strike, or if we should later compare the RX-78-2 with magnetic coating to the Freedom. Ultimately, whoever was selling the Gogg and Googhn respectively to their higher ups must have used their respective mainstay machine as a baseline for explaining why these big boys are a much better alternative to a Ginn or Zaku with swimming gear. Food for thought: I don't think it's ever mentioned anywhere, but I always assumed that the Abyss Gundam's underwater cruising mode was supposed to be based on the Goohn's, much how Gaia Gundam's MA form is based on the Bucue. The Zno needs to break cruising mode form to fire its palm phonon masers and its missile launchers end up looking to ocean floor, but the Abyss and Goohn can both operate at least two different sets of weapons that can fire to the front while in cruise mode.
Thanks for the comment and the goons got lots going for it, while mounted on the face the goon can swim by something and do a drive by shot, also can be upside down and shoot up while not breaking cruise mode. I do wonder how difficult using the hands on aqua or goohn would be, especially in intense scenarios. Visually the aqua is great so it's nice that the goohn shares its vibe & concept in a way. Also right I should of used the zaku / gm when comparing since there the on mass machines. I also should of mention how the proto type gogg was going to have missiles on its hands instead but water currents got in the way which would of been similar to the goohns layout and made it much more threatening, while I do like the gogg I would trust the goohn more feels like it's more versatile.
In the Cosmic Era due to ZAFT creation of N-jammersanti nuclear systems they have to use batteries to operate their mobile suits. Though the Freedom and Justice Gundam both have N Jammer cancelers which allows them to use nuclear reactors.
Well, there's the GNMA-04B11 Trilobite from Gundam 00 season 2, and according to the wikia at least 7 units were built. Although classified as a MS, for all intents and purposes the OZ-08MMS Cancer is basically a marine MA, lacking legs to operate on the ground unlike the OZ-09MMS Pisces. AOZ Reboot loots of new amphibious units, starting with the MAN-08S-M Helios Mariner, essentially an underwater version of the MAN-08S Helios which itself is an improved version of the OYW MAN-08 Elmeth. Then there's the ARZ-124HBIIM Aqua Hambrabi, which technically its an add-on for the ARZ-154 Barzam (ReZeon's slightly improved version of the RMS-154), which turns it into a marine MA. This one actually got a Premium Bandai HGUC kit, though you need to buy the AOZ Barzam separately. There's actually two versions: a red ReZeon version and a dark blue Titans version. Last but not least, AOZ Reboot also introduced the trasnformable AMX-003M Gaza M and AMX-008M GaZowmn Marine Type, though the former I have yet to see in MS mode.
AOZ as a whole has a shocking amount of amphibious MS you think they had a quota or somthing. Prob put MS names on a wheel and spun to see whos next to be amphibious