you will get in trouble regardless of your templates being on the server or client
My view is that you will get in significantly less trouble because manipulating an HTML template that is rendered on server side is much easier to manage and adapt to a new design than finding nitpick jquery selectors across the app that depend on a specific div structure.
Btw, my post doesn't imply anywhere that a designer should redesign an app without testing. Therefore, your argument about testing is garbage.
Rather than "finding nitpick jquery selectors" I use a client side framework (backbone.js) with a lot of Views which makes my development faster vs using server side templating, so I cannot share your opinion.
My view is that you will get in significantly less trouble because manipulating an HTML template that is rendered on server side is much easier to manage and adapt to a new design than finding nitpick jquery selectors across the app that depend on a specific div structure.
Btw, my post doesn't imply anywhere that a designer should redesign an app without testing. Therefore, your argument about testing is garbage.