What is your plan you have laid out so far?
Providing a guideline of what you have in mind(details of your application also) would allow other members to provide further recommendations rather than having to list out every item that you may already have outline.
As USER1211 suggested - stating your plans and ideas would provide suggestions.
One option would be to create a dummy member in the new dimension and associate the dummy member to all the historical data .
For the future years data your New Dimension would have specific members linked to it anyway.
Hope this helps.
My high-level work plan is:
1- Do a full backup (snapshot) of the whole application for worst-case scenario when I would need to restore to a prior state
2- Export level-0 data
3- Edit exported data to add a dummy member from the new dimension (say, "NewDim_dummy")
4- Add new dimension to the plan type
5- Build the new dimension from csv file (including the dummy member)
6- Import lev-0 data that includes a member from the new dim
7- Aggregate plan type (all years, all scenarios, all versions)
8- Update all web forms, business rules, and objects in FDMEE to include the new dimension
Did I miss anything big?
Any data loads to change?
Any smart push to recreate?
Note, if this is like PBCS you might be able to amend your forms by exporting, editing the XML and reimporting. Ditto the business rules.
Any of these; -
Smart View 'templates'
Interfaces / integrations to other systems