Frank,
No offense is intended here but the link you posted should be titled "signature licks" as you are able to name the song each one of them comes from as he plays.

A generic riff is one that is common for the genre and is heard in many songs.

Just pointing that out to keep down confusion of term "riff" in the context I was using it.

John, no offense to you, but not every one uses the program just for backing tracks. It is great for that but it is also marketed as a songwriting tool. In fact it's recommended to songwriters in the number one selling songwriting book right now.

If I was only using it for accompaniment of covers, I would still want more lead guitars. Why, because the ones that are already in there make me want more.

I agree with Bob about the size but that hurrdle will have to be addressed somehow as it's going to increase no matter what new instruments are added. I'm sure PG is aware and working on that. Which is why I suggested generic riffs based on genre - because that might cover more ground with less lead tracks.

However they decide to do it, I"m glad more lead tracks are coming.
This is a wonderful product. I love it.