A Tokyo arc wouldn't be the same as in Ai Yori Aoshi. I deem some of those arcs useless because you knew who the end girl was at the end, so who wanted to waste time on some ditzy glasses maid or the like.
But we have a very special dynamic in Umi no Misaki with three potential girls. Fumizuki learned a lot from Ai Yori Aoshi and it shows. I don't think a Tokyo will be useless, but we can achieve the same character development by staying on the island.
If I were Fumizuki, I'd save Tokyo for the epilogue with Shizuku.
Oh, and if there they were to go we'd lose out on volume covers like this....
