The plugin installer area is somewhat hidden, especially for new users. Typically the list is very long, and the install dialog is definitely out of the visible screen area. Also tedious to scroll there on multiple installations.
I would suggest to add an "install/new" button in the J! toolbar. As a shortcut/anchor to the current position.
Or even a submenu in the J! menu bar. Maybe this applies to all "new/create" menu items. e.g. all J! core menu items with "new..."