This may be a subjective question leading to deletion but I would really like some feedback.
Recently, I moved to another very large enterprise project where I work as a
I think your aghastness is qualified :) I can't imagine that the program is properly OOPified. Classes are a bit tougher to classify, but methods are easy: 1 behavior per method (that's not a rule, but it should be). Behaviors can't possibly be even close 1k lines of code. At least, as far as my imagination will take me.
Classes, on the other hand, can represent many things but they should represent something. If it is difficult to tell what the class represents, then you have a problem.
Now, I half imagine that you are well aware of these concepts and I'm preaching to the choir. So, I'll just pretend like I didn't go off on a tangent there and answer your question directly:
Yes. Very unfortunately, it is remarkably common for large enterprise projects to have code that lazy. I have worked on projects almost as large (yours shoots anything I've seen out of the water) and my first tendency is to start breaking things up into logical components, particularly in places where I intend on making changes. I can't handle that kind spaghetti, it's too irritating.