That still leaves an imbalance wilsonq2, and plenty of opportunity for the complete generations to argue about who gets what.
I can't speak for the OP's grandmother so I'll use mine as an example.
When my Nana died she left behind four children and five grandchildren. We were the complete generations.
My mother has two children, me and my brother. She had one grandchild at that time.
My aunt has three children. She also had one grandchild at that time.
My other aunt has no children.
My uncle has no children.
In your will, my mother, her three siblings, and the five children belonging to my mother and aunt would be the complete generations and be left something. The two great-grandchildren would not represent a complete generation and would not be left anything in your will.
The OP's grandmother made that an equal share to everybody, so lets assume you will do the same to your complete generations, meaning that in my Nana's situation you would leave nine equal shares to us as the complete generations.
But is that fair?
Not in the eyes of the OP's family. They seem to think that a bequest to the OP's children is also a bequest to her, meaning she is getting more than her cousins because her children are benefitting while they have none (yet) to benefit as well.
My Nana's four children would each have an equal share, but what if the two childless ones felt that their sisters were gaining more, since they had children also getting a share? What if my mother said she should get more because my aunt with three children was getting a share more than her?
They wouldn't (and didn't) do that, but in your will, unless your children all have the same amount of children each, it could still lead to problems if one or more is inclined to say "it's not fair", complete generations or not.
It's exactly the same thing, just moving it up a level from a possibly incomplete generation of great-grandchildren to a complete but unequal generation of grandchildren.
You could choose to solve that by leaving out the grandchildren as well and sticking to just your own children, but that's still no guarantee they won't argue, especially if one is earning more than another, or one is married and one not, or one has more children than the other, or a hundred other reasons they might think of to squabble over.
I'm not saying your way is wrong, but neither is the way the OP's grandmother chose. She'd done her best by the family she knew and loved, to treat them equally and give them all a considerable gift. They would all do well to respect her choice and be thankful for what they can do with it, regardless of what may happen in the future.