Maybe the originals' grandkids... 70-year-olds don't have 20-something kids.
2015 - 1983 = 32 years
Why is it so unrealistic that Han & Leia and Luke & mystery woman (I won't say Mara Jade anymore since she could be negated by the ST) waited 5-7 years after the events of Return of the Jedi to have kids? If they did, the first born would be 27 years old at the start of the movie and would still very much be considered a 20-something. 20-something doesn't have to mean 20 or 21.
Personally I'd welcome a movie that, while always aimed also at kids, I hope kids/teens on the big screen take a back seat to adults.
The caveat to that though is that out of any director in Hollywood, Abrams is someone I would trust with directing kids in a movie - while the plot of Super 8 wasn't all that great, the acting on the part of the kids in that movie was fantastic and even if just ONE of the offspring of the Solo/Skywalkers has a kid themselves, if that kid is handled in the same way the kids in Super 8 were handled, we'll be just fine.