I don't find :Glog all that useful (maybe I don't understand its value).
For me, :Git log is more useful. Change <leader>gl mapping accordingly.
nnoremap <silent> <leader>gd :Gdiff<CR>
nnoremap <silent> <leader>gc :Gcommit<CR>
nnoremap <silent> <leader>gb :Gblame<CR>
-nnoremap <silent> <leader>gl :Glog<CR>
+nnoremap <silent> <leader>gl :Git log<CR>
nnoremap <silent> <leader>gp :Git push<CR>
nnoremap <silent> <leader>gr :Gread<CR>
nnoremap <silent> <leader>gw :Gwrite<CR>