Concise Idea: when you end your attacks your turn is done. No fortifying.
Suggestion Idea: No fortifications permitted (consider it trench warfare where your armies stay where they are unless they are attacking).
Specifics: As indicated, once you are done attacking you are not allowed to fortify at all.
Why it is needed: Another type of gameplay (would give 4 different kinds of fortification games). This would force players to really consider where they are placing their reinforcements as they could not rectify mistakes by forting. Gameplay/strategy would be difficult as your main army could be trapped if you don't place your armies properly at the outset.
Just a thought...
(I did a search and didn't see this mentioned before)
I am serious...and don't call me Shirley.