Internal structure problems

[webbnissen]

We have a couple of hundred thousands indexed pages in Google from our site, start page have pagerank 5 but sub pages have allmost no pagerank at all. Start page have a quite big link index so I guess its because of that the pagerank decreasing so much. Even if we don't plan to change layout it sounds smart to prioritate some sections before others.

Any suggestions?

if start page is changed to few is Google quite quickly updated from that or is old sub pages involved anyway?

If I put a sitemap link on every page, should I expect the pagerank increase on that page and have a better control of the sharing? With all our pages it sound quite long time to get the sitemap to get high value. Or should I expect some results on next Google dance?