I have three suggestions, what do you think?
first idea you can do a claim limit per person/id because you need more space for larger companies...
second solution could be to let you claim like 3 or 4 times and let you build all over the island you claimed a bit of land. so that other person have chance to build on it too.
third one is in my opinion to give the map a few more smaller islands. you travel for hours between the landmasses. so a few more islands won't matter...
In fact the devs have to do something about it...