An option to loop sample with crossfade allows for smooth loop creation without having to use an external editor, and doesn’t force you to hard code any sample changes (so you can move the loop points around)
This is implemented in shortcircuit, and (I think) many other soft samplers like Kontakt.
I thought I’d use shortcircuit screenshots to explain the basic idea:
1 - a basic loop
2 - a crossfade loop - we get to place an additional line cursor which determines where the crossfade starts.
3 - so here’s how it works:
when the play position hits ‘c’ the volume level starts to decrease until play position hits ‘d’ (orange line). But at the exact same time as c-d is fading out, the a-b region is fading in (orange line). a-b fading in plays superimposed on c-d fading out. This means that there are no clicks when the loop restarts as we faded in a-b, the region just before the loop start point. This really makes creating smooth loops hassle free.
I would really like to see something like this implemented in the renoise sampler. Hopefully it shouldn’t cause any issues with 09 effect and other things. Thanks 
(From reading the board, shortcircuit seems quite popular here, but if anyone doesn’t know and wants to try this out it is free at http://vemberaudio.se/shortcircuit.php)