Not my answer butThe following mappings were adapted from Drew Neil's in his Practical Vim is to create the following mappings:
:nnoremap <Leader>n nzz
:nnoremap <Leader>N Nzz
So,They will make n
will go to the next match as usual and <Leader>n
will go to the next match, centering the screen. You could also drop <Leader>
from the mapping to change the defaults and have (next) searches also centered.