Thanks so much for your reply. I’m truly sorry that some of my adjectives felt too forceful to you. As such, I’ve softened them.
Perhaps some context will help clarify my position:
I get the impression that many of Scaler’s features are designed for users who don’t already know harmony, and that’s fantastic. Scaler cleverly opens up, and perhaps demystifies, the world of harmony for them.
I happen to have degrees in music, so I’m approaching Scaler from a different point of view. I’m an accomplished songwriter, and I thought it would be fun to play with Scaler’s song sets as a way to find chord progressions—that might not occur naturally to me—that I could use for inspiration while writing.
At the time of my original post, I was writing a song that’s in B♭major/G minor, and much of the song was already complete. But I was writing an additional section and thought I’d browse Scaler’s song sets for chord progressions that would fit my song. This is where I discovered that there’s no easy way to do so in Scaler.
Although Scaler can do something as sophisticated as forcing all song sets into the F# Locrian natural 6 scale (for example), it cannot simply play them in a specified major key or its relative minor (as is appropriate, depending upon whether the song set is major or minor). Put differently, while Scaler can do some truly wild and crazy (and inspirational!) things (and bravo for those!), this more fundamental feature was overlooked. 
As such, doing so currently requires calculating the distance in semitones from the original key to the desired key, then manually choosing the transposition. Not a big deal for one or two sets, but if one is scrolling through dozens of song sets, that becomes impractical.
Since no one has asked for this feature before, perhaps I’m the first user who had already begun writing a song in a particular key that I needed Scaler’s song sets to match, rather than using Scaler as a tool to begin a song from scratch.
All that said, I’m thrilled that you understand the request and that you’re willing to consider adding this functionality. And, again, I apologize for any unintended offense.
Scaler is a truly remarkable piece of software, and I look forward to its further development.
