Should a Generation in my Legacy go Immortal?

No, considering you seem to like killing off sims. I wouldn’t do so either though because I like generational play.

I voted for the founder because something about the first sim that I have created has a special place in my heart. It seems like after they have passed on it is extremely hard for me to carry on the family. Also, the founder could be like a guardian angel watching over the future descendants.

Hey, this gives me an idea. I've just started back to playing Sims 3 and was planning on going with a Legacy. I believe I am going to go this route with her. She is still in college. My plans with her are to let her finish school and find 7 more sims. With those sims, I'm going to start up a new world, and start it out with those 8 sims.

Having an Immortal Founder restricts gameplay, having a founder that can die in a Legacy game allows you to make room for more sims

Definitely not! I personally think your first generation sims have gone on way too long for you to concentrate properly on the next generation but that's just me.

You play on such a long lifespan that they're almost immortal anyways ;)

Nope. How many generations were you planning on going through?

Personally, my first sim always has a special place in my heart. I'm actually considering moving her and her partner into one of the secret worlds and leaving them there and letting everyone else get older and pass on. She also has achieved the "Bestselling Author"aspiration and is capturing the lives of her loved ones in books.

No. I've been following your story and I do agree with those who say your first generation has gone on too long :p I know you have a soft spot for River and Haruo, but you gotta let them go :D

I thought they were :#

It's a legacy, so handing something ( depending on what you choose ) down through generations. It doesn't seem much like a legacy to me if the very first generation is still alive at the last.
That's just me though.