Yeah, mostly because you'd be alright getting it early with Auri, and is a damn blessing for Tarnished Judas, the former having items that revolve around Broken Hearts while the latter gets powerful the more broken hearts he has.

And while the cost is alright for Isaac/Auri, Tarnished Judas is...a bit weird - he pays in Broken Hearts for the devil deals already, so just having his power correlated with time instead of choice is...problematic. Thus, the idea that you'll fight Angels within the Sacrifice Rooms to get your stuff they took as compensation would make more sense.

I like the idea, i'm currently making items for fun as to eventually maybe make an item modpack that has alternate, tarnished and tainted items. Also items that i just think might fit well into the lore of the game and introduce new mechanics. However Valefar's gift is a mechanic that is worth exploring as a starting character since the item is most interesting the earlier you get it. Thank you for the interest :).

For simpler explanations:

Auri - Gets Dark Crown, and cuts both the Broken Hearts and time limit in half. Preforming a Sacrifice rewinds time to the start of the 3 minutes (This is to give a risk/reward system due to Auri having use for Broken Hearts)

Tarnished Judas - Timer becomes nonexistent, but getting a Devil Deal item has a 15% chance for an Angel to swipe it away from you. Preforming a Sacrifice gives you 3 Broken Hearts and the stolen item (This is to ensure that Tarnished Judas does not outright benefit from having this item.)

Some ideas for 2 "particular" characters

Auri - For Isaac, he is but prey within Valefar's trap. However, what better a thief than one who took the identity of someone else? The gift becomes merciful on Auri, also giving her Dark Crown, and reducing the broken hearts given by 1, as well as removing the payment of Broken Hearts altogether...but the trap now becomes merciless on her: Every 3 minutes, she will gain a broken heart, and the only way to reset the clock, is to offer a sacrifice. Time will rewind back to the start of those 3 minutes...but is it truly worth it?

Tarnished Judas - The crime of selling the son of god, is a welcoming signal for many a devil. Tarnished Judas can no longer get Broken Hearts and sell his fate from this item, giving him free devil deals. However, grabbing one has a chance to be plucked by the heavens, and unleash suffering...unless you offer yourself as a sacrifice with 3 Broken Hearts.