First of all, Wigfrid is mini Bee Queen now. Both can sing a song that can cause mob to panic, except Bee Queen's song cannot be interrupt by being hit and Bee Queen has a song that boost its follower movement speed and attack speed, wouldn't it be nice to have it on our Wigfrid.
Thought out my testing I notice the meter as it fill up, progressively require more hits to do so.
Here I would like to suggest to add songs that can only be use on second slot and third slot, while not changing what is already added to the game. I would categorise them as tier 1, 2 & 3. Songs that are more powerful it couldn't be perform in the early stage of battle(or early stage of performance), it can only be perform in the heat of the battle, especially on tier 3 songs I would consider them the "Ultimate". Those Ultimate are unlock when Wigfrid hits the third meter and will consume certain amount of meter upon usage. In the current version there's only two song that consume meter to perform, however due to meter progressively harder to build it is easier to not have any buffs just so you could refill and use it again. Currently those two songs are not worth to spam with though. And currently a fully filled up meter doesn't do anything, having tier 3 song provide a use and refill instead of "I'm full there is nothing I can gain from this"
Some idea would be, buff X for X seconds, restore X upon each use
Also I find it hard to believe a renown performer cannot perform a song without holding the lyrics, did she also read from the script as well while on stage? Maybe add an option to right click "eat" the script literally, to remember that song word by word as she eats it. Then she can perform it later with an icon without taking the inventory space. And eating another lyrics would replace the existing one as favorite.
Just throwing some of my ideas out