Having too much abstraction is a problem. Having too little is also a problem. There is also the case where even a well-abstracted codebase will suffer becaus

Having too much abstraction is a problem. Having too little is also a problem. There is also the case where even a well-abstracted codebase will suffer because of the particular feature requested. Even the best codebases will need changes in 5-6 files, if not more, if the feature doesn't fit with the rest of the system. It is trivial for stakeholders to request something that doesn't fit with the rest of the system, where one can then declare the system 'poorly abstracted'.