In my opinion it is the fan grill that is the biggest problem. It is a safety liability to the company to have an unguarded fan, but that requires the fan to blow directly into an obstruction. The result is the fan has to churn at 13,000 RPM in residue laden turbulance depositing more gunk on the fan blades, and presenting a surface that will eventually face load and block the machine from breathing.
I see you are one of the original backers, if your warranty is gone like mine you might consider doing What I did, providing you are comfortable with your tinkering skills.
I’m very happy with the results. Removing the obstruction to airflow (which also benefits cooling), allowing much easier cleaning of the fan from the rear, and eliminating a periodic maintenance requirement. It also runs a bit quieter.
I was a little reluctant to tear into my precious, but with care it really isn’t a big deal. I am much more comfortable with my ability to pull maintenance on any part of the machine, which will come in handy when tube replacement time rolls around.