I'm playing a game with the Lanun, and I think this went overboard. A work boat costs 40% of a worker, which makes the ports very easy to build early game compared to last version, and the trade bonus is enormous. I'd suggest moving +2 trade on the harbors to Optics and +2 trade on the ports to Astronomy at the very least.
Current emperor game on quick turn 161 has me at 820 GNP, closest rival at 289, and the gap is only getting bigger.
You are aware that these new Lanun economic options are worse than what the Lanun were capable before. And by far? That change is a serious nerf, not an improvement.
Obviously you did miss the possibility to get freshwater lakes / terraform tactically before. Or you didn't care to do the maths.
No its not to strong and comparing them to the clan is not really the best way forward. Rather compare it to a forest cottage of the elves to get the picture + that you can at best! get 2 usually only 1 of those per city in the early game and these yields have to offset any sea-tiles in the cities fat cross. (Sea-Water offers not so interesting Yields in comparison to Land to start from. Even for Lanun. Especially for Falamar.)
So to be as fair as possible in your favor and lets equate the additional yield of 4/4/12 (and please do so for the very start of the game as you wish but be fair in your comparison. Agriculture / Calendar / Education are not really late game techs. And Fishing isn't exactly a starting-tech) for 5 Water Tiles in the fat cross.
Please compare that to the additional yield possible at 5 Land tiles and see if its all that hot still.
(thats roughly 1 Mine (due to general-low-production of Sea-Tiles and optional working of tiles on land), 2 Agricultural farms and 3 Cottages at an average River-setup. 5 Tiles needed for a regular yield of 6 Tiles seems a real gamebreaking advantage... Yes... For even regular civs. + you can't go past that cap with harbors but can very easily on land. Please sir get your maths right. And no its not many turns of difference to achieve above mentioned.)
And thats the best equation in your favor which is encountered regularly. (With 4 / 2 the exeption and 1 / 2 or 1 /3 much more likely now and even likely more useful economically in the 1/2 case many times.)
+ very importantly you forgot that Work boats are not built with food unlike workers unless you run conquest which inflates the time to build them to about the same time as Workers or just a bit less. (This is especially true since one of the advantages of the Lanun is to get additional Food from water and the general low-production of Lanun cities near water. And you could get 3-4 Harbors with them before + the huge freshwater lakes around those cities which makes it even worse. By far.)
All in all if anything to weak for a civ with an economic affinity! (read: should be significantly better akin to elfs and the likes) to water, not to strong (for a civ that is actually disadvantaged in other regards i have to stress. Some of them as unneeded in FFH2 as land-combat

).
Dominating the AI means not very much btw. ... If you can't cope so well with other civs like you do with lanun might be that you are not as good playing them as you are playing lanun? (which may have many reasons.)
Building 3 Cottages (which equates the advantage of 2 Ports built.) early is no real problem for any civ really (if you aim for it, which is not a bad way to play by many accounts). Which completely takes care of the advantage in commerce respectively and doesn't use up a unit, just a bit of time.
But im not really suprised that such calls whould come up the day the change occurs. Whenever the numbers seem high someone complains that its overpowered.
Yea! Nerf anything advantageous to death until its unplayable! Really good way to design a game

.
Good that the Team deosn't heed all those calls otherwise FFH 2 would be a much worse game.
If anything Lanun whould deserve a building later in the game (like at Trade or optics) that gives all Water tiles at least one Food if not one commerce added to that. Or alternatively one hammer and to river tiles as well

.
To at least partially offset that other players tiles / improvements get much better later on in the game.
Not further reduce their only real advantage to nothing.
Because you can do it by turn 30 when other civs are putting down their first farms for +1 food. It's a timing issue.
This is just wrong (exept perhaps for marathon). At the time lanun reach fishing most civs (those who either start with chants or agriculture) are halfway to cottages already (agriculture / farms is pre turn 20 at worst, Turn 0 at best (fine if you can bash a nearby civ to get a worker or 2. Doesn't work with Workboats) + have a worker out if you need that badly) and have allready build farms especially the higher you go in difficulty or the faster a game you play.
+ you cant build a workboat pre-fishing (unlike workers pre-agriculture / pre-education). Which means about the time you have built a workboat you might be as far as building cottages otherwise (turn 40-50 at worst.)
+ Lanun can't get good yields (or any Yields for that matter) from the sea pre-fishing unlike a land-based city (big disadvantage right in the early game you mentioned).
+ Lanun are not only Hanna the Irin (Financial beeing a good trait is no suprise really.).
For Falamar it might even be worse to start water-heavy as opposed to a cottage-start.
As odd as it sounds. Can still build a costal city + ports and research fishing later (freshwater issue / brewery comes up as well under those circumstances.).
(+ Mysticism is only a short hop away thanks to chants needed for education unlike if you go for fishing first.)
Unless of course you don't prioritize either Education or Mysticism. Thats not to blame on the other civs then though.