A few thoughts
- UX is not always UI. Most discussions on this topic end up being about UI aesthetics, the Metro look, and what not. UX is about the user experience. Eye candy certainly has the bling aspect to it, and might even get you into the door with certain clients. However, I do feel that for complex products (ERP certainly is one!), what is more important is that the application functionality and application data should be structured around the way people *want* to use the application. It should not be based on how product designers or even UX experts think that people *should* use the product.
tl;dr - You can improve UX significantly by making small changes in a legacy user interface.
- From what I have seen, big bang approaches to UI overhaul (or even functional overhaul) almost *never* works for a large complex product. Think about chipping away at the problem instead. Think about the 80/20 rule of getting the most bang for the buck by making a few quick changes that can significantly improve the UX of your product.
- Consider a survey or face to face interviews or best, both. If you can measure the benefits of the changes you are making, or even get enough qualitative anecdotal feedback (especially from power users and from key clients), you will have a much stronger case for making more far reaching changes.
- This is a topic of debate and some controversy - but consider the Net Promoter Score. It gives you at least one way to measure what your clients think about your product.