Personally, I don't feel that the song rotation really adds much to the class. The issue is it makes the class very....uneven. As you say yourself, Army's Paeon just feels bad for example. While there's certainly things that might be done, ultimately the biggest issue can be best emphasized in how bad the rotation is in AoE. Wanderer's Minuet feels amazing ST, but useless AoE. Mage's Ballad is okay ST, but god-tier AoE, and Army's Paeon is very meh for both ST and AoE.

I personally don't feel like this song weaving mechanic, while cool for SB as something new, actually adds much to the class. In addition to making the leveling experience feel worse, the actual gameplay, in my express opinion, also just feels worse.

What I would do is change it such that Wanderer's Minuet is a stance, alongside Mage's Ballad. WM for ST, MB for AoE. Army's Paeon just flat out being removed because it doesn't feel good to begin with.

For bloodletter, you could consider upgrading it into sidewinder, and then buff rain of arrows into shadowbite, but make mage's ballad only buff shadowbite.

Bard is mostly about procs with a side of DoT maintenance. Army's doesn't really improve this gameplay in a way that feels good, mage's feels weird ST because you have to watch bloodletter like a hawk just to know when it procs, but WM feels good overall. And you will still get that weird 30 second cycle simply because of refreshing DoTs and having 80s cooldowns for burst damage.

Just my thoughts, as a non-bard main. Obviously though, if WM Becomes a stance, something needs to be done to make it so the sound effect isn't identical to the level 80 ability's thing, because that's also dumb.