The one product I think Zoho should consider building which would really round out the sales & marketing side of its business is a headless CMS. That headless CMS can then be integrated with Sites, landing pages, campaigns, marketing automation, social, etc.

I'm sure you guys could spin up a first iteration very quickly, as it isn't much more than a database and it could potentially transform a product like Sites so it could properly be used to host blogs, etc.