It would be nice to be able to independently specify the height and width of the bars, text size, and scale of the buff icons, separately from the overall frame scale. I say this because scaling causes the bars to look horrible for most scale values due to alignment issues.
It would also be nice if the proximity bars would show player names in their tooltips (preferably class-colored).
It would be great if there was an option to select which groups get included in the buff check. In a typical 25-man raid, we have groups 1-5 actually in the raid zone, and everyone who's on standby in groups 8, 7 or even 6. It would be cool to be able to exclude those people from the buff check, just like you can with the buff buttons themselves.