I do not see this as a major issue with SEO (someone correct me if I am wrong)
It's a big issue with SEO. The whole "cool uri's movement" has turned this question totally around. There is nothing that Google explicitely likes about neat and sweet urls. Basically Google does not care. There are some other things why non-cool uris might become some limitation. So, it's not like like that cool URLs would result in good placements in search engine result. Implementing cool uris is like releasing 5 or 10 tiny tiny breaks, that would add together and improve the WHOLE BUSINESS POTENTIAL of a website, NOT JUST THE RANKINGS IN SEARCH ENGINES (this is a big myth).
Remember, cool uris are so called on page factors (seo factors that occur on the site that will be in the results). BUT OFF-PAGE FACTORS (like link popularity) WILL *ALWAYS* BEAT ON-PAGE ONES.
If I should specify it in a mathematical language: for every amount of on-page optimization of site X, there is a amount of off-page optimization to ANY OTHER SITE Y WITH ANY HTML CONTENT , that woul result in Y to be listed above X in search engine result pages. This is why so-called google bombs work.
Talking to the homesite url question, the main problem is in duplicities. Search engines hate dupilicites - it's added work with no purpose. So, they basically take only one page of the set of duplicit HTML outputs and discards the others. And this is the loss of ranks (Google Pageranks ets.) - for example every link to
www.modxsite.com/homesite will be discarded. So this is the reason.
MODx helps you build sites that perform well in search engines – in fact, we think it's a great SEO CMS. Human readible URLs that Google loves is part of the reason,
Actually, we are really far away from this. The implementation of cool uris is in almost any cms TOTALLY UNDERESTIMATED and basically does not release above stated breaks 100%. Just an example: MODx does not respond properly to site.com/doc vs. site.com/doc/ issue. Remember, site.com/doc and site.com/doc/ are totally different documents in the HTTP language. There should be a standard for CMS to choose one of them and stick to it. The others should be redirected. But the right way - there are several HTTP redirection method, bud only one passes pagerank...!
The other issue is remembering the old aliases - this is the big one. If someone change alias, all the old links are lost, so the pagerank is lost. This is a break.
I've just started developing a SEOURLs plugin, that should put all the differences in a row, output good redirections, put all links on the site into a good form... but it would take some time.
