I have a site that got hit by the March 12 Algo changes. It's entirely built on HTML and CSS, no CMS used.
When I reviewed it, I realized:
1. the site could use more content that G bot could use to understand the pages better.
2. I need to push the content higher above the fold.
3. The template needed to be responsive (mobile, tablet, web, etc.)
So I'm about to launch a new template. I basically have to fit the old content and the new content in a new HTML/CSS template. It doesn't look much different outside of pushing all content higher up the page. It uses a new CSS file reference and responsive code.
My question to you guys is it Okay to roll this out slowly? I can usually edit about 50 pages and the site is about 800 pages. I'd rather have Gbot eating up my new content additions this week rather than the 4 months it's going to take me to make all the changes.
Users really won't notice much difference, the new design will be better for them, because the content is higher on the page. But as users move between the new and old templates, they will need to download two differents CSS sheets.