Honestly, I'd be happier getting the lower-level things tweaked to be more in line with updated systems, than rolling out a big new [mana-expensive] WunderKind.

The ELR brought a formalization of "evoke" for single-target spells [became a mass-version] as well as implementation for mass spells [became a single-target version].

I would love for the mass versions of several spells to be usable against a single target [Lore or Song knowledge or MC unlock, like Disrupt or HoldSong work]. Looking at Depression especially, but I would like to get HoldSong back to "just a single target" if that happens to be what I'm aiming at.
And Noise. Single-target Noise--while still letting me-the-Bard do effective casting--would be fantastic.

And I would love for the other direction to work, especially Rage becoming a mass effect. Or VibChant. Or Unravel [hold me still while I shudder in ecstacy].

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ELR also saw "RT-adders now give instant RT!" conferred on Slow and <whatever that Paladin spell is>... and left it right on the table for Depression (which gives adder, like those) & Rage (which gave actual RT). Despite both of those being higher level than either of the ones that did get the benefit. (And one of those, was a Spirit spell benefitting from the Elemental Lore Review.)

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And of course, there's that whole "permit the 'renew' verb to actually trigger Runestaff flares," too.

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Any one of those would be an immediate add to all Bards, particularly casters, with an emphasis on runestaff users.

And should be a hell of a lot easier than coughing up a whole new spell design.