I have 2000 visitors/day but i have to change the theme om my site. The structure will be the same on the root page but on some pages i will have new links, new photos and new text. The problem is i am afraid to change the theme, i heard bad things like "don't change the site if the site is working", what should i do ? My plan is to change the site theme and submit a sitemap to google. Help Help Help !!!
i think if u create new pages and also change them for all old page then it's no problem. just remember "no broken link".
change theme should be ok since you didnt change the content and links. (try to keep same Meta tags and title) to be safe, save your old version of the site and implement it back if the traffic or serps really drops a lots.
As long as you don't change the content and other stuff that might affect your ranking, its ok to change.