The first thing to remember is not to change the entire design at once.unless it's totally horrible.

The prototype should never be better than than the final version because what we try to give is awesome design which work awesome as a static version but when it come to dynamic view developers keep changing things.that will completely change everything you need to change accordingly

sometimes people think that single page apps are better.it's true in some cases but not in all the cases

trello is the best example it can be a single page app but they dint.pjax is what you can really use for dynamic design but still when it comes to micro-blog or blog the ajax will just fine. but you should really try pjax technic for mega apps.

i work on django so thats what i suggest for others using pjax is awesome