Pretty much the same experience here. Been (quite happily) using Ceramique since it first launched and have been through quite a few tubes over the years. I have seen the same thing - gradual climb in temps after about 1-1.5 years mounted. This pump out phenomenon happens, but it is definitely not a fast thing, certainly not something that should stop you from using for relatively long-term periods of time on bare die. It doesn't just stop working suddenly one day, you just notice that your load temps start to gradually increase and take that as a reminder to reapply at that time.
Nice to see how well Ceramique holds up against the best out there - exactly on par with ICD and only a few degrees below the absolute best. I'll just stick with it for now.
Thanks for the work, awesome read!