Personally i hate nested boards and sub categories i would not like the change
A example of a forum with far too much categories, all containing several"child board" each containing other nested "Child Boards " is http://www.fractalforums.com
, i hope GC would not do something alike, browse that forum for me is a pain, also because new post are not visible if are done on "child board" so each time i have to explore all the labyrinth.
for what you wish is much better learn to use searchAnd as far as improvements would be sufficient allow to "tag" the new topic
using your example of Tutorial i will found useful Tutorials tagged as you suggested ( GIMP basics, Quick Tips, Animations, Text Effects, Special Effects, Photo Effects, Design, Uncategorized/Other, etc.) that for sure will make search easier...BUT i will found horrible them not as tags but as nested boards.Also because many of that categories often overlap, not a problem if are "tags" because you may use several tags so the same tut may be tagged " Quick Tips" "Animations" "Text Effects" "Special Effects" " Design"
BUT if instead would be new nested boards ...where you will post a quick tutorial about animated , special logo effect ? ... under "Quick Tips" ,under "Animations" under "Text Effects" or , "Special Effects" or under" Design" ...you will be forced to chose 1
And then to search quickly you will need a magick crystal ball telling you which of the 5 possible adapt boards was chosen
I already have similar nightmares when browsing fractalforums please, please don't do the same here on GC