Going off your Little Mermaid 2 rewrite, I imagine building a wall around the kingdom would hurt Ariel & Eric’s relations with not just their daughter, but with their entire kingdom too. I think the wall would make fishing and sailing a lot harder for everyone, plus imagine all the money/resources wasted on building that wall. You think Eric at least would realized these large-scale consequences of his/Ariel’s hasty actions ?
The wall causing tensions is a good point.
Truth be told (this is in general, but it also applies to my remake), I always imagined that ever since Ariel was Queen fishing was outlawed a long time ago, and they found another way to make money. It wasn't a popular choice, but Ariel and Eric managed to do it.
About sailing, though...I think that sailing was outlawed as well, because people didn't want to face Morgana.
Either that, or there was a specific area for ships to sail. Though I could see people getting mad about that if they needed to secretly sail or something.
Plus, the sea isn't really that safe anymore...King Triton isn't as reluctant as he used to be to cause problems for sailing ships. Morgana also is willing to wreck ships too.
And to answer your question: I don't know. I think that they probably did consider it, then did it anyway.
This isn't a confirmed thing, but I had this idea that the wall wasn't just a wall. It's a magic wall that keeps out natural disasters, like storms. Ariel made it as part of keeping the general populace happy when she became queen. The wall works really well, so even people who are anti mermaid don't get upset about it much.
