Here's the part where I'd normally go into detail about all of my choices but really, what is there even to talk about? The ones that are good are good for incredibly similar reasons. I guess I can mention some hot takes though...
Undertow Spillway - These are unordered within their tiers, but for what it's worth, this is my favorite map in the game. I think all four modes are fun even if some are obviously better than others. Rainmaker on it miiiight just be my favorite map mode combination in the game but I'm not sure. The map feels completely reasonable both on offense and on defense in every mode though and I don't even think Splat Zones is that bad despite most people thinking it sucks.
Robo ROM-en - Overhyped as can be but I still think it's pretty good. To be completely level with you I think people got a little googly eyed over there being real flank routes around mid. You're not going super far through them most of the time but it's very nice to drop onto the ramp on the right side of mid when the other ramp is accessible as easily as it is. That whole deal carries the stage to being good for me because otherwise it's super chokepoint-y just like most of this game's other maps.
Lemuria Hub - It's kind of mediocre on some modes but I think it's really cool on Clam Blitz and a bit overhated on Rainmaker. The big thing most people seem to hate about it on Rainmaker is the ramp carrying the shield up like 30 points or something but...really, isn't this something both teams can abuse? This isn't a problem that limits how either team can play like so many other maps in this game. If you make it far enough to pick up a Rainmaker that's at 20 points left then that's still the enemy team's fault, plain and simple. The one exception is with Kraken but this is still a problem in basically every Rainmaker map mode.
Hammerhead Bridge - This one in particular is definitely bias but I'll say that it's still easily the worst map in this tier and I only think Splat Zones is worth playing. For this map it's just really fun to play around in mid and I think defenders have enough options otherwise.
Marlin Airport - This map just feels extremely cramped and every important point of the map has way too little cover. The foundation for something great is here and if it got a """rework""" then I could see the minor changes they made to other maps taking this one from bad to fantastic though.
Humpback Pump Track - Can someone help me understand why people like this map on Rainmaker? Do they just tolerate it because they don't have many options? It feels like around 80% of every game is spent not in mid because of how easy it is to get to that one checkpoint. From there defending and attacking both feel horrible because the optimal places for both to stand make it impossible to hit one another while also cramming everyone into one or two spots. It's literally what everyone says about you needing to wait for special and bank on that working to go forward just like with so many other maps but it's cranked up to eleven here. On other modes it feels AoE favored to an excessive degree. I like that it's in the game because mid is extremely unique but it's a bit sad that it plays better in Turf War than any of the actual game modes.
Mincemeat Metalworks - This one isn't a hot take but I just wanted to talk about something. This rework did
nothing for this map. Most people would say that it's better than it was on launch but the changes were so minor that I wouldn't even go that far. The literal only change I like about this map is the block under the center bridge that lets you squid roll onto the enemy's plat just a little easier but that change is so small that it's basically completely ignorable. I considered putting Eeltail in its own tier above these two because there is a massive gap between the tier above and Eeltail as well as Eeltail and these two. Mincemeat Rainmaker can be kind of fun sometimes in solo but even that isn't the case most of the time. Might actually be my least favorite map in the game overall.
Overall though, I'm not a HUGE fan of most of the maps in this game. They're tolerable and there are a definitely few that are pretty good, but they don't really hold a candle to Splatoon 1's best maps. Have you seen Mahi in THAT game??? It's incredibly dynamic, open and in general just feels like a playground in a way that Splatoon 3 only replicates with Museum...during the high jump challenge. Undertow might be my favorite but even that is only on par with some of the just high tier maps from that game. Meanwhile on the other end you have Mincemeat which is bad in an insanely boring way. I would take Saltspray back in this game if it meant getting rid of it.
To end on a more positive note though...
Same list as before, but I crossed out all of the maps that weren't in the game on launch in black and all of the ones that needed improvements in like this weird maroon color. This game's Mahi and Hammerhead were some of my least favorite maps in the game before their reworks and Undertow would have been down two tiers.
Obvious takeaway here is this - the maps of this game aren't perfect. Obviously. They're extremely limiting and most of them play extremely similar to one another. It still is worth bringing to light that we've at least come a decent way from the start of the game. If Nintendo is bent on designing their maps like this, then they've at least shown that they're getting better at it. Not perfect, but I'd never expect perfect consistency and the more recent duds we've gotten are at least just a few steps away from being solid as opposed to needing massive changes like some of the earlier bad maps we've gotten.