Is this meant to be a drop-in replacement for Salesforce or just another CRM? There's a built-in advantage to choosing the tool that everybody uses and that's compatibility. If you look at 1000 data integration or marketing automation tools on the market, 1000 of them will have OOTB integration with Salesforce as a selling feature. Just to be realistic, building a better CRM won't be enough to replace Salesforce.