It is irrational. What do you want it to rate ? Social behaviour ? Or " osdevel level "?
If you want stars to have a osdev meaning, how about White wolf ascension ones ?
* : Ability to read, reproduce fully guided tutorials and understand their general idea
** : Ability to do small changes and adaptations from existing code to your idea. Your kernel really looks like someone elses.
*** : You need to understand that under your Os, there is a hardware, a firmware, some peripheral. They can be flawed, or designed badly. You know how to practice black magic needed to achieve a goal. You know how to make major but no huge structural change in OSes.
This includes abusing triple fault to reboot, working around CPU/emulator bugs, doing some nop nop between sti and hlt, using recursive paging..
**** : You know that aside your OS, they are many other designs, some are very bizarre. You know how to analyse something really alien. This knowledge allows you to make drastic changes in an OS, create weird ones.
***** : You have realised that conceptually, your idea of kernel has some flaws . You know how to spot them, and you have a feeling how to make your kernel " the real thing ". You are working on them. But you are sad, there is a lot of work, and you don't want to break compatibility. But you are correcting them nevertheless. You start flagging deprecating APIs..
" oops, i shouldn't have imaginated a fork/pthread_cancel method "
With this amount of stars, you are able to correct the reality of some OSes.
****** : You are an OS guru. You leave a something behind you, good people follow you and this feed your wisdom.
You are able to make some idea appear in some OS. You may even have some bots quoting you on IRC, or some people stealing your graphical compositors .
Not only you are able to change your OS, you are also able to subtly influence others.
*******: You are not in the same world as us. Your influence extends to other spheres, like hardware, libc, algorithmic..
Do you know people who match those ? How many stars do you give yourself ?