In the 84p map you have a choice of how you want to expand. You can either
a) Expand slowly but indefinitely building, upgrading and maintaining propaganda offices
b) Expand fast but deliberately, only conquering select provinces that give you either victory points or resources
c) Only expand until the expansion penalty is too severe to expand anymore. This is the point where you can either stop your expansion or transition into a)
d) Expand quickly and indiscriminately, conquering everything in your path. If you have the units to leave behind low morale won't matter except for resource production and even if you leave the provinces open it won't matter if there are no enemies left for the revolted provinces to bolster.
e) A mix of the above, depending on the situation
To sum up, you have many options. What will get you killed is, not considering them.