Well, yes. That's just part of your project to determine whether you should switch. You do of course have to evaluate all of the costs and benefits. (And those costs and benefits are very specific to your environment.)
If you are considering the switch, then you should at least pick one of your transformations as a
test case. That will then tell you how long it takes to convert one of your XSL files as well, which is another thing you need to know. Your two questions are:
How much will it cost me to convert?What are the benefits if I do convert?
And then you have to compare those two things and see whether the second exceeds the first.
As to whether there exists an XSL-FO to JasperReports translator, have you looked? A general Internet search for a start, then a closer look at the JasperReports site would be my recommendation.