Soccer is big business in Europe and UEFA rules provide for tie games leading up to the championship series be settled by two games, a home and an away game for the teams, with the goals scored and away goals determining the winner. Extra time is only added if the two teams are still tied after this phase, in case they play two 15-minute periods. If the teams are still tied after these periods, a sudden-death penalty kick contest takes place to decide the winner. It is an involved process but the winner has a legitimate place in the championship series after passing such hurdles.
Throughout soccer history there are tales of outmatched teams playing a defensive game to force a draw with a much better opponent. This is a valid strategy in soccer and has been forever. It's only us Americans that can't seem to handle ties in our sporting events. Call it a draw and move on. That's the way soccer has always done it.
No, overtime doesn't have to automatically happen whenever there is a draw. There could be two winners. What's wrong with that? I wouldn't mind having a tie and having two winners. I like the idea of sharing the glory instead of just giving it all to just one person or one team.
The group stage should have winners and losers based on traditional points systems, goals differential and then away goals. If everything else is tied, doesn't it come down to a coin toss or some other random chance? There are plenty of tiebreakers up and down the table for teams tied in points. Going to overtime shouldn't happen because European club teams already play enough games in one season as it is, and teams may not want to sacrifice players any more than they have to in this case.