I've built large systems with RethinkDB, and proprietary NoSQL DBs. My experience is this: if you need to query any significant volume of data, you must have in

I've built large systems with RethinkDB, and proprietary NoSQL DBs. My experience is this: if you need to query any significant volume of data, you must have indexes. And once you start figuring out the indexes, you're designing a schema. So it's best not to shy away from schema design up front, and evolution during dev. Otherwise you risk very poor performance. On the requirements front: dialog with management and users often degenerates into handwaving. A concrete prototype can help clarify IMHO. Suggest you break out one small piece of the legacy system and prototype a new solution. Disarm the scared seniors by emphasizing that it's throwaway. When the users see something new, shiny and better you'll have the political backing to face down opposing noobs and seniors. That's a double edged sword, as you'll also have the pressure to deliver. Good luck!