I recently came across an issue when trying to build a SSAS project containing modifications to the standard AX Cubes.
When building or rebuilding the project, I got 1 047 (!) errors with the description "Dimension [x] : Only dimension attributes and attribute relationships can have translations in Standard Edition."
The only solution to this is to (try to) modify the SSAS database in SQL Server Management Studio by some heavy scripting. Or of course upgrade SSAS to Enterprise Edition which I really don't know is legal without licensing Enterprise Edition (I'm trying to clarify this). Anyway it's a valid upgrade path regarding to the information given by Microsoft for SQL Server 2008 R2 (Version and Edition Upgrades) on MSDN.
The system requirements for AX 2009 doesn't contain any information saying SSAS Enterprise Edition is needed and neither does the general SQL Server reqiurements.Until further noticed and official information is given from Microsoft, it's worth having this in mind when deciding which edition of SQL Server to use together with AX 2009.
The only information from Microsoft I have found on this issue, is in a draft document titled "How to add financial dimension to Dynamics AX default cubes" (PDF) from the EMEA Dynamics Support blog on MSDN. On the bottom of page 3 and the beginning of page 4, the following information is given:
In general, I think most customers will end up designing their own cubes and modifying the needed Role Centers accordingly, to avoid all the struggle with the default cubes.