we know at this point in the books that most of Randland is in chaos, mostly at the hands of the forsaken, their dogsbodies, Fain and total fools. As we know chaos is the element of the dark one and the more he sows, the stronger he gets.

Breaking the tower back in book 4 BEFORE the 'let the lord of chaos rule' order was IMO, a masterstroke. the Tower has been the symbol of the light for millenia and sometimes symbols are more important than the actual thing they represent. we can certainly see what happens to the world after the split. the endless summer, masema going insaner ect.

im currently re-reading TSR and what struck me as intresting was the fact that in this book the tower split, LTT's essence appeared and Rand starting down the slippery slope of madness. Rand first speaks as LTT when telling Lanfear to eff off. 8 books later and the tower is healed around the time Rand finds some inner peace. "the land is one with the Dragon" indeed

so IMO the tower struggle is mainly symbolic of the Dragon Reborn's struggle to keep order whole before TG. he needs the world behind him otherwise he'll lose. with the tower whole he gets 1000 or so channlers, Garath Bryne and his army, the tower guard and the people in the city proper and the outlying villages.

think of it this way:
Loial gets Rand the Ogier
Lan gets Rand the Malkiri
Egghead gets him TG and the tower Aes Sedai and the Younglings
Elayne gets him Andor, Cairhien, the Kin and her armies
Mat gets him cannons, the Band of the Red Hand, possibly the seanchan and by extention half the westlands and moiraine
Perrin gets him the wolves, Gheldihan, Mayene,the mock Aiel, the Two Rivers and probably Galad and the whitecloaks
he already has the Sea folk, Illian, Tear, Arad Doman, Asha'man and most of the Aiel.

course Rand could have united the westlands so much easier but where would the story be?