It's matter of taste that is correct but how is this plot more believable? I think stranded on island is more believable than letting your player friend be the pretend boyfriend of MC. Also, for plotwise in this game MC puts himself in this situation but in Lost in Paradise they found themselves in that situation and they try to adapt.
LiP, gives more choice. You can follow Netori, Netorase or Netorare paths. Also, there are more than 1 options for both MC and his wife. I also liked LiP characters more. Cornell is a sleazy fuck, I have no idea what his sister's goals either. LiP story is more intriguing IMO. My only problem with LiP was too short and ended too abruptly, other than that it's better in every way.
Though, this does not mean I did not like this one. I like both, yet I favour LiP over this.