What does he need to achieve in order to be considered the GOAT? His achievements can never rival Eddy, but we are in a different, far more competitive era. 
It is crazy the level he is going to have to maintain, year after year, in order to get his Palmares on a level that is in the discussion. 
But there really is no limit to what this guy can win:
GC+stages in all three Grand Tours
All 5 Monuments
World Championship
Olympics
GC+stages in all the big seven stage races
Big non-Monument one-day races
I think some combination of most of these achievements and 100-150 career victories, in the current era, as a GC rider, would be enough to cement him as the greatest cyclist of all time.