OFX is not a replacement for Yodlee. OFX is a passive specification that relies on each data provider writing to the spec. Yodlee uses OFX, but also uses screen scraping and other methods to get data from the many sources not covered by OFX. If Mint dropped Yodlee, many of their data feeds would disappear.

Data aggregation is a messy business. No two companies have the same feed options, nor do any two feeds work the same. And for consumer-facing data, Yodlee is the best.