Sounds like you want a standards station, not a soft AC. You probably aren't in my target demo, which would be 35-54 female, with a minor percentage of men. I'd make it accessible for 55+ since they always help cume numbers, but I wouldn't cater to them. It's about being the next generation Soft AC station, not the one that plays Neil, Barry, Barbara and a bunch of 40+ year old music.
I think a big reason that supersoft AC hasn't taken hold in most markets is that it's not contemporary enough. A lot of traditional AC programmers seem to be embracing tempo, but I think that a Soft AC can work in the right market and circumstances if it plays mostly songs from the last 20 years or so. As we've found out with the Adele phenomenom and Whitney's passing, ballads and mid-tempo pop records still work...they just have to be the right ones. With the lines between CHR and Hot AC blurring, AC trying to keep up, and all three formats sharing too many artists, the door is open for a Soft AC resurgence. It just won't be the "Soft AC" we grew up with 30 years ago.