Is using a rhetoric element plagiarism?
In my opinion what you are suggesting is brushing up against plagiarism.  Done just once as you suggest, it will surely not be a problem.  But if this is an example of something done more systematically in your writing -- or is indicative of the way you look at borrowing others' ideas and words -- you may in fact have a problem down the line.  Certainly I see room for improvement.  

Plagiarism is the act of using someone else's ideas or distinctive language without sufficient attribution.  So your explanation as to why you are not plagiarizing is not really convincing: the language was distinctive enough for you to want to copy it.

Now you have taken a rather short "rhetoric element" and changed it a bit, from


  Wise men have had the brilliant, although not fully correct idea that A


to


  Wise men have had the brilliant, yet slightly wrong idea B


I think it's an interesting question why you changed it.  Did you change it because you didn't want to copy too many words verbatim, or because the second one reads as better to you?  It's not a trick question: both impulses are good and ought to be taken further.  You feel less bad copying a smaller number of words, so keep going with that: keep going until the first six words are no longer identical, at least.  In terms of reads better: experienced writers know that anything can be be made to read better if you put more time and work into it.  A main task of a writer is to come up with language which is (i) original and (ii) optimized for the subject matter, and in really effective writing these two goals are confluent and mutually beneficial, not antithetical.  

What piece of writing is really so good that it needs to be repeated as is from one situation to another?  (That's not a completely rhetorical question, and there are a few positive answers, but they are few.) Since you are writing about new ideas and new work, you should (the vast majority of the time) find that new words are more appropriate than old ones.  

In the case at hand: I don't find "Wise men have had the brilliant, yet...." to be rhetorical gold or anything close to it.  If I am honest, to me it sounds like the kind of hackneyed academic writing that young students sometimes use earnestly and older students and veteran academics either mock or use ironically.  (And a tip: that the brilliant and wise are men is going to be noticed in a negative way by some.)  I suggest that you practice slinging your own phrases: soon enough you'll be able to do as good and I hope much better than this.  (I thought about showing you half a dozen similar phrases to indicate it's no big thing, but I decided not to because I don't know the intellectual content, and choosing language divorced from content is part of what I'm criticizing.)

Good luck.  For further reading about what it's like to encounter many short passages of your writing coopted with minor changes, I recommend this piece.  (And to gain some respect for the complexity of these issues and remember not to be too critical of others, I recommend this piece.)