Your irregular boundary needs to be drawn as a polyline and not a series of separate lines. This polyline can then be offset whatever distance you want using the 'parallel' command. Is this what you mean?
I don't use use the straight/curvy leader command either. For exactly the same reasons (ugly). Here's what I do:
*Set up a DIMENSION (in your template dwg). You will need to change the comprehensive scale factor when you first start a new job to be the same as your chosen MSCad job scale.
*Cad Tools>Customise>Toolbars tab. Select Dimensioning category and then drag the LEADER tool onto your drawing space. Close the Customise box and then place your Leader tool wherever you want.
You now have one button to insert leaders which can be straight, curvy and annotated or not. Give it a go.
You can already do this by going to MsAnnotate>Fonts/Style or >Labeling Defaults. You can create your own style name and go to town with sizes, fonts and all types of other settings, or you can just change the standard LY styles to be any font that you want.