SD3 isn't really what I'd think of as a dating simulation since it doesn't have stats of any kind (unlike say True Love, which seems a lot closer to what you're describing).
On a more practical level, what you've described as a possibility for SD4 is effectively two games. If the PC ended up with Becky, I can't see Mike, Molly or Melissa remaining in his life. Conversely, if he ended up with Molly he can also kiss goodbye to Becky and her family. You also don't mention the possibility of the PC ending up with Alison, who is the character who has the most possibilities in my opinion.
Given that SD3 took approximately two and a half years to create, I wouldn't expect to see a game that's twice the size of that any time soon (not to mention that Goblinboy has said that he'll think twice before trying anything so ambitious ever again).
More subjectively, both of those options sound very similar to the earlier games to me. Thematically, Camping Trip is about the choice between love and sex, which was such a strong theme that it was reused for SD3 (and option 2 in your suggestion). Option 1 has a lot of similarities to SD2 (at least in outline). Neither option develops the characters in any way, they just place them in similar situations to what they've already been in.
YMMV of course.