Of these 75% of my sites, only 2 use the same system - and even then they are using different releases and have different capabilities and methods for implementing site changes. Each system has different strengths and
weaknesses, but only one or two of these systems were developed with any consideration of search engine optimisation in mind, and even those that have been designed to consider this also have their own problems.

I think that there are a core set of requirements of areas that I would love to have control over on all of these systems and here are a sample of these:

1) Allow content management on the vast majority of pages. Quite a lot of these systems allow a lot of control for some deep pages, but it seems to me that a lot of the time you can't content manage the home page of the site, and in many cases it seems to me that designers create a website, and then create a system for a user to add new pages to the site, without the facility to make changes to existing content. I think if a system has been created to manage a website, then you may as well content manage anything that may require changes.

2) Specify <title> tags for pages independently of any other factors. I think web designers may often be unaware of the importance of the <title> tag for search engine optimisation, because on a number of occassions in the last couple of years I have seen the title tag being set by association with the internal name for the page and also frequently with the file name used in the URL. So when you pop in a nice optimised title for a page, it suddenly re-writes the URL and makes the page difficult to manage via the CMS.

Then you have to start arranging a 301 redirect from the old page to the new page - it frankly can become a mess. Then add in the fact that many a CMS will automatically use the short title they specified when creating the site as the anchor text and this leaves me very surprised when changing the title of a page that it breaks the design in a number of other locations.

3) Incorporate a rewrite module of some description. This would allow us to incorporate keywords into page names where appropriate, and would prevent ugly URLs that I find a CMS will frequently generate automatically for a site. Failing that, it allows you to give sensible pages names that your users will understand.

4) Allow changes to Meta data on a page by page basis. I've worked on a number of CMS systems that have had to be heavily modified to have this capability. Globally set Meta Descriptions (and to a much lesser degree Keywords) do not give the site any advantages from an SEO perspective, and may in fact induce penalties, especially if page titles are also duplicated across the site. This is because if a title and description are the same for every page, you are essentially telling search engines to expect the same content on each of those pages

5) Have the facility to set to use <h>, <b> and other markup tags or have an HTML view where you can physically change the code to include these and other areas. This allows you to highlight to search engines (and users of course!) particular sections of the page as appropriate, rather than all text being added to the site in a standard <p> tag, and thus losing the opportunity for some easy boosts.

Please - don't misunderstand me here, with the vast majority of these websites, we have found work arounds that circumvent the systems in place for the areas that were not controllable via the CMS. However, these workarounds have created additional work for all involved or we have had to place extra emphasis on other factors that we have better control over to balance the inability to make certain changes.