Generic Advice for Writing a Thesis
solipsys.co.uk
solipsys.co.uk
Personally, I find clarity and focus the most important qualities of a thesis. The former requires and displays deep understanding and writing competence, and the latter requires and displays planing and the ability to identify a specific issue (out of all the things one could write about).
Cleverness, however, is not so high on my list of requirements. Many hard problem exists in a space of trade-offs, without a silver bullet solution. Understanding and effectively communicating these trade-offs is probably more useful than a single "clever" solution.
I've been through this. I failed my PhD first time round and was nearly refused a viva voce (oral defence) because my thesis was "too clear" and the material was "too obvious." I'd written it for the supposed eventual hypothetical reader, and not for the people who were going to examine me to see if the material was worth a PhD. Fortunately my internal examiner insisted on the viva, and on the basis of that I was granted permission to re-write and re-submit.
Second time round there was very little additional material, but the emphasis in the writing was changed so it was no longer "here's how to understand this" but was more "look at the amazing results I've proved."
It went through "on the nod."
So what you say is true with regards what you want to see in a thesis, but if you want to get the degree, the emphasis needs to be different.
Unfortunate, but true.
Added in edit: Tomorrow I'll re-read and probably add a comment to include the above main point, that I'm giving advice on how to write to get your degree, not how to write to be clear for the reader. Thanks for the feedback - very helpful.