Just having a connection shouldn't be enough, you should need a "good" connection, basically what influence does now. The lower your influence is the harder it should be to hold/take. Not just captimes but spawn timers for infantry and vehicles.
Yes it should be possible to do a epic last stand and try to hold a base until reinforcements can secure a connection but it should be harder. Because right now the continent map really doesn't have much of an impact on a battle which sort of removes the strategic element to the war. Cutting deep into enemy territory should have penalties, just as being able to cap around an enemy stronghold should have bonuses.