I personally think that trying to ascertain a top 5 when you are talking about something that is 8+ decades old and covering so many genres as well as international is almost impossible.
most people would say that Kirby has to be there but then the Europeans would say Herge and Uderzo must be there also. Japan different again.
So....
why not open it up? Create a number of categories like:
Story-telling, action, drama, space, fantasy, sci-fi, longevity, strip, etc etc...
I suppose what I’m getting to is that some people might put Charlie Adlard in a top 5 for story-telling when you consider he’s been so consistent with the walking dead. Eduardo Risso as well. You would never put J. Scott Campbell or Travis Charest on this list even though they are both great artists.
Space may be Kirby, Moebius
Just my two cents (worth the same as two pence now as well).
Cheers
John