this should be a big one 
i discovered in the past an anomaly of Revit, but these days I studied the problem and reversed the anomaly in a good tool to reorder nonshared parameters.
It works only with the next families that you will develop. Not available for existing families.
So:
1. make a new generic family
2. make 5 parameters in the same category (like Dimension) in this order with the names :
one
two
three
four
five
3.press ok. they will be listed under Dimension from top-down like this:
two
three
one
for
five
4.make a new project.
5.in the family press Load to Project buton.
6.switch back to family windows and close them all (no need to save the family).
7.from project browser under generic model right click on family and click e Edit.
8.in family rename your parameters like this
2two
3three
1one
4for
5five
9. press ok then load to project (the same project!), then press Override existing version.
10. switch back to family windows and close them all (not need to save the family)
11. in project browser under generic models right click on family and click edit.
12. in the family editor under type properties....Ups! the parameters have this order:
5five
4for
3three
2two
1one
13. rename your parameters to your old names. Now they are looking fine
five
for
three
two
one
14. to keep the nice order of parameters do not resave the family by opening from the edit family path from project (like edit family buton or edit buton from project browser).If you want to inspect your family open it from windows explorer and save it from there.
IMPORTANT OBSERVATION
If you want to upgrade the family (more parameters or another order)
1.open the family.
2. put more parameters
3. put numbers before the names of all parameters(for every category) to indicate the desired order (big numbers goes up)
4.press load to project (ATENTION THE SAME PROjECT SO DON`T YOU EVER DELETE THE FIRST ONE. IT`S LIKE A TWIN BROTHER FOR THE FAMILY. THEY SHARE THE SAME BLOOD FROM THE DAY THE FAMILY WAS BORN). Overide the existing family.
5.in the project browser under generic models right click on family then click edit
6.in family editor the parameters are reordered accdording with your numbers. just rename to old names(remove the numbers)
7.use the nice ordered family
For all the folks that are inlove with Family Editor
i discovered in the past an anomaly of Revit, but these days I studied the problem and reversed the anomaly in a good tool to reorder nonshared parameters.It works only with the next families that you will develop. Not available for existing families.
So:
1. make a new generic family
2. make 5 parameters in the same category (like Dimension) in this order with the names :
one
two
three
four
five
3.press ok. they will be listed under Dimension from top-down like this:
two
three
one
for
five
4.make a new project.
5.in the family press Load to Project buton.
6.switch back to family windows and close them all (no need to save the family).
7.from project browser under generic model right click on family and click e Edit.
8.in family rename your parameters like this
2two
3three
1one
4for
5five
9. press ok then load to project (the same project!), then press Override existing version.
10. switch back to family windows and close them all (not need to save the family)
11. in project browser under generic models right click on family and click edit.
12. in the family editor under type properties....Ups! the parameters have this order:
5five
4for
3three
2two
1one
13. rename your parameters to your old names. Now they are looking fine
five
for
three
two
one
14. to keep the nice order of parameters do not resave the family by opening from the edit family path from project (like edit family buton or edit buton from project browser).If you want to inspect your family open it from windows explorer and save it from there.
IMPORTANT OBSERVATION
If you want to upgrade the family (more parameters or another order)
1.open the family.
2. put more parameters
3. put numbers before the names of all parameters(for every category) to indicate the desired order (big numbers goes up)
4.press load to project (ATENTION THE SAME PROjECT SO DON`T YOU EVER DELETE THE FIRST ONE. IT`S LIKE A TWIN BROTHER FOR THE FAMILY. THEY SHARE THE SAME BLOOD FROM THE DAY THE FAMILY WAS BORN). Overide the existing family.
5.in the project browser under generic models right click on family then click edit
6.in family editor the parameters are reordered accdording with your numbers. just rename to old names(remove the numbers)
7.use the nice ordered family
For all the folks that are inlove with Family Editor