Is there any major change in p2 mechanism in Eclipse 3.8? I tried to install Eclipse 3.8 plugins via p2 dropins mechanism but its not working at all. It is not able to resolve the plugins. Plug-in perspective is also missing. Also the bundles.info is not coming up in org.eclipse.equinox.simpleconfigurator.
I suspect that your dropins are failing to install because they have dependencies that are not resolving in your new install. The standard behavior for dropins is to ignore plugins that cannot be installed. The user doesn't get any feedback on the problem. That's one of the reasons that dropins approach to installing plugins is not recommended.
To debug your current problem, try to install the plugins you are trying to install via dropins by using the plugin install dialog instead. You will see a report on why installation cannot proceed and will be able to proceed accordingly.