FWIW, this is how I solved this on a modified K2 site. I will have several authors and public commenters will be required to register as subscribers. I just changed the login redirect and site admin tab and the dashboard privileges and that took care of it without a lot of work. The login redirect now goes to the main blog page and the admin tab reads "My Profile" and goes to the profile page instead. Novice type users never have to deal with the dashboard, though I can get there if I need to. The following cites the line changed and which file it was in:
1) Changed line 170 of wp-login.php to
$redirect_to = 'index.php';
((I changed wp-admin to index.php))
2) Changed line 7 of /wp-admin/menu.php to
$menu = array(__('Dashboard'), 'read', 'index.php');
((I changed value from 0 to 20. I also saw where someone had changed 'read' to 'manage_options' instead.))
3) Changed line 47 of template-functions-general.php to:
$link = $before . '' . __('My Profile') . '' . $after;
((I changed /wp=admin/ to /wp-admin/profile.php/ and Site Admin to My Profile.))
ETA that part of the above code turns into a link after posting on the forum and is confusing. Here it is hopefully more as it appears, I just took out the expected <> around the "a" tags and replaced with ^:
$link = $before . ' ^a href="' . get_settings('siteurl') . '/wp-admin/profile.php/"^' . __('My Profile') . '^/a^' . $after;
This was the simplest approach and worked great for us. The login going to the blog's home page makes more sense to everyone. The commenters and the other people who write posts at our org can click on “my profile” after they log in and go to something familiar that makes sense, without being thrown by landing at the dashboard. I just let people sign up on their own and change the roles of internal people who want to post for them.
It’s pretty easy maintenance. WordPress rules. Note that I am not an expert and can't guarantee this nor can I help you fix it if you break it. I did this without breaking my site tho and of course you should always back up the files first.
If you want to see it in action, go to http://dce.unm.edu/dceblog