[Scott Hebert]

Well, if you don't think that fortifications have a decent ROI (which IMO they shouldn't; that's not their point), you would still choose a fortification that has the best ROI, if nothing else to minimize your problems.

From an economical standpoint, the two best Fortifications for ROI are the Castle and the Wizard's Tower.

I think it would be interesting if, as an exercise, IW made all Fortifications equal in price (the most logical price would be 0) and made them quantitatively different in other ways (Admin Ratings, defense Ratings, Supply Ratings, etc.). Then you could have the 'defense fort', the 'money fort', the 'cheap fort', etc.