Because research in itself, especially in the tech+finance world, is quite technical lol. That's why most people don't/can't pick the right coins, because they're simply incapable.
Does anyone know of reliable sources that can provide unbiased overview of limitations and potential problems that a coin and their devteam is facing?
There's no one-size-fits-all source to see the cons of a project. It's mostly just use-case and economic viability that determines a project's general viability is in the top-level. And there's the basic stuff like determining if the project/team is fake, and the like.