I wish Leverkusen would have won the game as this draw is kind of annoying for both of them. Dortmund couldn't get any closer to the top and to Bayern and Leverkusen couldn't turn their dominant game into important three points. No need to discuss that a win would have been preferable for obvious reasons, but it is true that Leverkusen has the game against Bayern on their home ground. To tie a game against Dortmund is ok and Bayern will have some weaker games, too. But we can already see what's needed to stay level with Bayern. Wins, wins, wins.
The game ended draw between Leverkusen and Dortmund might be expected result by many people, but it's frustrating for both teams, especially considering the missed opportunity to keep competing at the top. Dortmund's failure to close the gap to bayern, and Liverkusen's missed chance to convert their dominance into three points, adds a big disappointment that could hit their mentality remembering they have to fight against Bayern for the tittle race. They know Bayern wont easily drop points off against other teams.
While Xabi Alonso had a great test to evaluate his team after the draw, there's still a opportunity for his team to secure the lead in the league by having the upcoming game against Bayern on their home ground. Leveling a score line in a game against a strong opponent like Dortmund could be acceptable, and as you point out, Bayern may face some challenging matches as well. This draw should be a reminder for Alonso to realize that the competition's intensity and the high standard requires to stay competitive at the top.