...here's the small bit of code to remove to get rid of the gap.
In templates > fusionbb > showtopic_p_row.php
Find:
Code:
<!--SIGNATURE-->
<!--EDIT_PRINT-->
<br /><br />
<br /><br />
<br /><br />
<br /><br />
REMOVE:
Code:
<br /><br />
<br /><br />
<br /><br />
That would put it back to the exact same spacing as 2.3. I hope that helps with your decision.