When people state that certain characters in the top ten strongest, i think they tend to forget just how many characters there are In Naruto. The top ten is pretty overcrowded as it is with little space to maneuver .
The simple fact with jiraya, is that he died without showing Enough feats to put him on top. He never won any fights in the series,
And more importantly he can no longer get any more feats while other characters have the potential to overtake him.
Even kakashi is showing that potential to surpass him if he hasn't already.
Not hating Jiraya just being realistic here. it's obvious that when people claim he's in the top ten they've not put enough consideration or thought into there decision. or they are not up to date with the current manga.