This is more of a feature request rather than a support request (unless it is already there and I didn't realise).
I suggest that the Events Manager widget is also controlled through a fully customizable template. The current way it works only allows you to specify an inline template (through wordpress admin) for one event in the widget which is repeated for how many events you want to display. However you cannot control the overall widget.
For example I wanted to move the 'all events' link to the top of the widget (rather than the bottom) and I had to modify the core widget() function in /events-manager/widgets/em-events.php which means it will get overwritten with the next upgrade.