I have given my statements about my displeasure with sea many times. In the least there's a lot of unit variety. I feel that every unit is fiddly to use, things like hunter vs duck it's hard to fight for zero attrition(very tiny margin of error), but possible. Siren counters scallop, like a skirmisher counters a riot, but the range of this skirmisher is like 500 elmos and it has a massive turning radius, similair to how mace v scalple worked. So it's very easy to be uncareful and lose a lot of HP. Bouy works very well against ships tbh, getting 60 HPS to outregen siren's DPS. But float to fire feels very bad in gameplay, like some kind of fencer/halbird combo, where you stop to fire and lose armor(surface) to fire. Also, bouy's low damage doesn't work well vs tanky ships that will always be able to out run them. Shields and cloak are incredibly strong at sea too, submerssable units underwater can advance easilly with shield cover. Surface units can drain shield with attacking ground(except for rare super deep water cases). Shields do work very well against all kinds of attacks, the only weakness is draining shields or AOE, or a claymore droping a mine inside of the shields. I find it hard to control everything at once(I don't use control groups), and it's very hard to apply guard direction while your units are on the move, I find myself applying guard to the wrong unit/structure or the wrong kind of guard frequently.

When building a large mass of units, I will take very careful caution of sirens which will deal AOE damage to allied units as well as nasty Friendly fire. Scallop ball is by far the easiest to execute, because scallops fire through allies. When mixing grizzlies and ships I think it's sub optimal because, I'm not sure cause I wasn't paying too close attention, but I think my grizzlies fightmove works incredibly poorly with float to fire and incorrectly assuming the path is blocked because there are ships overhead to bonk, so they end up just standing underwater doing not much.

I feel that it's a struggle to get my units to fight the enemy well, and also I'm always running a fine line between winning and losing an engagement baised on positioning, AOE affecting alies, and Friendly fire.

P.S.:Lobsters are a growing source of enjoyment for me

Do you think it's possible to make a diferent AI for when a unit barely outranges an enemy, but has a large turn radius? something to give it a more angled approach, so it's easier to escape if the other unit decides to B-line for you? this is a tactic that affects land matchups as well, like scalple vs mace. When I have com upgraded level 1 with EMP I'll micro against a simgle ogre as such, when the ogre is facing my com directly, I commit to get in range, suffering the first hit of course. Ogre+dominatrix comes to mind aswell, where committing biased on how the enemy is facing is life an death.
Slower weapons with small margins of error also are more greatly affected by retreating, because of target prediction. I assume torpedos predict target like rockets do, like in Cyclopse V mass rouge, where when the cyclopse retreats it can shoot at the rouges because they are closer(they shoot ahead of the cyclopse) but when the cyclope advances the rouges will be forever out of range.