can you explain this to me? i've never used spreadsheets extensively so i'm clearly ignorant but my impression was that the only thing you could really (i know you can bend the rules etc.) is data transformation. when you say application is what you mean? i.e an ETL app or do you mean more than that?
The more that's been done in Excel, the more pain it will be to maintain it in Excel or port it to a non-Excel platform, because Excel is seductive for write-once, but horrible for maintenance, and the people in an org who have it as their main tool are unlikely to be either cognizant of the problem or devoted to spending effort mitigating it.