Pros and Cons of building a relationship model where all table ids are just "_id"?
There's no weighty reason to do one or the other.  Both styles are common and work fine.
AFAIK:
Pro: You always know how to join, as foreign keys use the same column name in each table, and join queries are easier to validate.
Con: You can't declare a supertype in your app that has the primary key as a property.  IE it's a relatively common pattern in .NET to have
public abstract class Entity
{
    public int Id { get; set; }
}

as a common base type for your entitites.
Some may argue that you shouldn't be adding synthetic keys to tables unless there's an actual need, but that's really a different issue.