Something like that would be cool - although I think we have more than just the 'Australia' corner issue here:
Take 'Africa'
Appropriately given the Oasis bonus system
29 regions, 6 places to defend, +21 doods per turn., attackable from 3 continents.
In Classic it has 6 regions, +3 doods and 3 defending points, attackable from 3 continents.
In W 2.1 it has 25 regions, +15 doods and 5 defending points. attackable from 3 sub-continents and Antartica (therefore, more-or-less a 4th (sub)continent).
Whilst adjusting values may help the defending-points-no.-regions-bonus-value ratio, continents would still not have enough close links to other continents in my view.
A river system would help, although, would it help link 'Africa' , 'Australia' and 'S America' ? Or maybe coastal ports would help?