Some things I would like in a Generations pack:
Toddlers
-Parent and toddler clubs
-Daycare playable career featuring neighbourhood toddlers
-Playpen
-More toddler beds
Children
-More childhood aspirations. Perhaps one related to the scouts. A collection aspiration would be fun for kids too.
-Bikes for kids
-Bunk beds
Teens
-Teen-specific aspirations like getting a boyfriend/girlfriend, getting an A grade, becoming popular,
-A few more after school activities for teens and kids such as joining a sports team, dance class, science club
Young Adults
-Stag and hen parties (would apply to any engaged sim from YA and above)
Adults
-Mid-life crisis with goals that suit a sim's personality. Examples could be getting a makeover, quitting a job, getting a new job, having an affair, getting divorced, wanting to get married if single, going to university, going on vacation.
Elders
-The option to make a will to decide who gets the sim's money and personal inventory when they die, and whether the house passes to a resident, a non-resident relative or soneone else. Sims could also leave money to charity and get a special tombstone/urn if they do.
-Optional canes (would also be useful for other age groups)
-Retirement party
Also, a Faithful trait for sims YA and above, who will never flirt with anyone other than their spouse once married