Context: I'm an embedded dev with only 2 years of solid experience. I'm the sole technical employee of a startup of 4 people. We have an MVP of our product out and are getting ready to develop the next iteration of it. The original MVP was developed by a partnered contractor team, with one older embedded dev doing everything software. I joined the company too late to have any input into the design of the MVP. The product is a gateway-type device: embedded Linux, messages come in one way, some limited intelligence happens inside, they come out on the other side.
The 'problem': Everything in the system seems to be chucked into a single SQLite database. Processed and unprocessed messages live in the same table (with one field used to indicate which one they are), provisioning related things live another table, even the logging and debug is done by writing to yet another table in the database. The system is written largely in python but the biggest part of it is a massive class full of wrappers for complex SQL which seem to do the bulk of the data manipulation.
All of this makes me uncomfortable, especially the messages part as it looks like a classic case of "database as a queue" design anti-pattern. That being said I find it difficult to articulate exactly why this is wrong to my non-dev boss, other than vague and nebulous mentions of maintainability, difficulty in introducing changes because of lack of modularisation, as well as of lack of clarity in how data flows and is being processed. It doesn't help that the contractor has "authority of years of experience" over my judgment.
Am I justified in feeling uncomfortable about this design choice? I mean, the thing works in principle. I know that the desire to refactor can be pretty strong, irrational and should not always be acted upon given business constraints. But then... I kinda feel like starting mostly from scratch only ripping out useful bits of the first MVP would be cleaner and take less time than working with the system created so far. But is it just my younger-person-hot-headedness?