:::::1. Wikipedia contains far worse articles than those selected for TAFI. 
 :::::2. I disagree that the thematic link is weak.  Since 2006 (when DYK and OTD were swapped for this very reason), the right-hand column has highlighted — from top to bottom — our most polished articles and those for which polishing has just begun.  The idea always has been to present both sides of the coin, acknowledging that Wikipedia is perpetually in development, with articles spanning the spectrum.  The bottom placement of TAFI (linking to articles that the community is encouraged to begin polishing) is a logical expansion of this theme. 
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 :::::Even setting aside the aforementioned themes, it makes no sense to divide a single section in that manner.  —