College of Transmutation is lovely, but I don't see the point of the line "provided the creature doesn't already have temporary hit points." We already have a mechanism that keeps them from stacking, why is this necessary? I wonder what the most useful things the bard 6 can create are, outside of scamming merchants. I kind of get why the pet is 14, but it would be much more fun at 3. There are subclasses like these where I'd rather they got everything when the subclass is taken and just have it scale. EDIT: I also like that this one has a spell-slot regenerating feature, I just missed that the creation feature recharged. I'm a little surprised by that, to be honest. The object is never permanent and takes your action for 10 minutes, and only lasts up to your bard level in hours thereafter. Doesn't seem like it needs a recharge mechanic but I suppose wily groups will abuse the heck out of this, even with the recharging.
Domain of Love is beautiful. Everything here is evocative of the domain. On top of that, it's mechanically sound. Really strong for small parties and still quite good in larger parties. I also like that they can use spell slots to reuse their level 1 feature.
Clockwork Soul is neat. Anyone who chooses not to use the Manifestations of Madness is a disappointment. Not adding to spells known is also a disappointment. I also like that they can spend sorcery points to reuse some of their features, and more specifically that it doesn't cost those points the first time they use the features.
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Restore Balance is weird. I think the reason they worded it this way was to avoid arguments about how advantages and disadvantages can be cancelled, and to interact with other reactions that might apply advantage or disadvantage (who wants to fight timing battles?). They could have worded it as, "the creature rolls without advantage or disadvantage and cannot gain advantage or disadvantage on the roll," which I think also avoids the corner cases around timing, but it's achieved with less words the way they have it now. I think the way they went might actually be more succinct and accomplish more than the alternatives, even though it reads as clunky.