If Heaven is a "place" then it's perfection is not tied to who is there and who is not there. Just as any mansion/home might be considered "beautiful" whether we know the tenants who reside there or not.
"Life is a personal journey."
Not everyone we love will meet the criteria to enter into heaven. However if heaven is truly a joyous place than I suppose those who are there will not be spending time thinking about those who are not. (I imagine there is no grieving/sorrow in Heaven.)