Simply because that's where I liked the sound the best. A Width value of 1.0 yields the direct output of the reverb algorithm, which was designed to have a decent stereo output. A value of 1.25 gives it a little extra stereo spread, which I like.
Note that having the Width control > 1.5 or so gives results that are a bit weird perceptually. We've since tweaked the stereo width portion, to make it sound better. So that should be there in the next release. FYI.
There are a few extra things that we'd like to add to the envelope section, including putting more modulation destinations in there. I agree with you that modulating the Wet Input would be useful. I'm not sure if we're going to get around to it before the initial release (we're focused on finding & fixing existing bugs, and on decreasing CPU usage), or if it'll end up showing up for an update. But your request is duly noted!2. Is there any chance of adding the ability for the envelope section to modulate (wet) input level? Seems like an obvious option to have. Useful for stuff like reverb throws.