It is true that Dortmund's busy schedule this month could be a barrier for them to gain full points at home. As you said, there were several injured players, however I think they will still win this game no matter what and it looks like Edin Terzic will arrange a good strategy so that his players can play optimally.
About the previous head to head match against Leipzig, that was a pretty good record achieved by Leipzig, but I think this match will be much different because both of them have their own targets. But again, every gambler has their own assessments and predictions regarding the results of the match.
Busy schedule is surely no big barrier for the Dortmund but for me most chances they could be tried their best for having better result from this match as after few years we have good chance for them to compete with champions Bayern Munich for the title race and their recent form is also allowing them for having good end of this season even now second spot is also settled with their last winning streak but if they are able to win this match then surely this could be interesting and things could be also entertaining for the fans as well.
But, here RB Leipzig is also having impressive record as they won two games and lost just two in their last five encounters, but we can expect surprising result as well because currently Borussia Dortmund is at their best, and they will be entered in ground with their full powerful attack for having positive end of this match and their rank could be also challenging for the Bayern Munich as well.