What about Cubase\ProTools killer feature in Renoise (at least in my case)?
An option to show two samples side-by-side and align them visually using markers (slice markers will do) would be a fantastic addition to this great piece of software.
For me personally, it’s the only thing i’d like to change in Renoise so far
Here’s a screenshot :
There are two mono samples in my example. Of course for stereo samples it will show two channels for each