I had a little debate (friendly one of course) with one of my work colleagues, caller Lior Alon about the usage and the necesasry of this technique. At the start of our conversation we disagreed on several things like: "It must stay for the good work flow", "This is by Microsoft design - do not touch" and more and more...
But at least we agredd that in some cases this ViewState is unnecessary and it has some disadvengtages that come over the adventages in some cases.

From the initial point of view, I would change the ViewState behavior. By defaut the ViewState of each ASP.NET web page is always on, so when you develop a new page you need to consider that the ViewState is on - so expect to amount of encrypted lltterals on the top of your page (according  the web server controls that you rendered on your page).

This issue has some disadvanteges as I said earlier:

1. Big size of data that comes from the sevrer to the client (response time concerns).
2. SEO (Search Engines Optimization) - Most of the seerch engines doesn't indexes the whole page (and I think non of then but I am not sure of it). The exsitance of the ViewState in the top of the prevent these search engines from index the relevant data from the specific page and here the ViewState takes its place. Here comes the question why the ViewState must be on the top of the page instread of its bottom?
3. By default the ViewState in on; In some cases, static pages contains web server controls that doesn't need to be updated from the server by the user demand. In this case each control has its own ViewState and it being populated to the bunch of the ViewState's encrypted data. (In that case you can develop this page using HTML controls that doesn't drag to the page 'added value'...

So, to the conclution...

ViewState is not bad thing, but like everything in life has some good and bad 'habbits'. After time of thinking, I think that the default behavoir of the ViewState should be off and the developer that creates her ASP.NET web page should be smart enough to use it wisely.

What do you think?