Honestly, nothing I have seen so far replaces Blutricity as a power system.
I'm not talking about the fact how it transmits energy from A to B to drive machines. Or specific, individual blocks, which is not a good way to characterize feature replacement. Any power system offers that. Your list would be as long as there are mods that implement a form of power. But the specific implementation of Blutricity itself - the way it worked, the near-perfect split of "easy to use, difficult to master", and the way it made the workings of real electricity visible ingame does not exist anywhere else. Or even the nebulous and difficult to grasp "flavor" of it all.
I'm... not sure what you're talking about. Nearly all the subtlety of Blutricity was utterly lost by a total lack of things to do with it except produce MJ, which was such an awkward way to do it that most people only bothered because they loved windmills. You can say you enjoyed maintaining the voltage, but how many alloy furnaces can you run?
The sad reality of Blutricity was that it was often "that thing that forced me to keep a lava block under my base for the sortron." It was magic, sourceless power prerequisites with a cool system that most users cheerfully ignored.
You COULD make cool system, but with only 2 things motivating factors for generating blutricity in bulk, it was a bad design. Unbalanced, lopsided systems are bad design.
I've had high hopes for UE, but it spectacularly failed at replicating any of the good points. It's hard to see what's going on, it teaches little to nothing to the user, it's somewhere between unintuitive and frustrating to try and get it working as a newcomer, and it offers little to no incentive for improvement when it finally works.
Well UE "just works". No one uses the voltage numbers anymore (even Calclavia) and Aidan is removing the electrical units from the tooltips and switching to RF (which is internally what's used, he says). The reality of the Minecraft universe is that a very basic and idealized model of power flow is far more valuable to users and developers to a more specialized (and in Blutrucity's case, computationally expensive) models.
Don't believe me? Do you know why developers are cheerfully and vocally migrating to RF? It's not because of FoTM reasons; it's because the Buildcraft team has been trying to make MJ more distinct as a power source with increasing limitations besides (dumb power pipes, sources and sinks). Those design restrictions interfere with a lot of developers, and so they're leaping off the MJ ecosystem.
Alternative models besides RF exist, by the way. Most notably Factorization and Blood Magic have very unique alternative power generation schemes that continue to delight an amaze me. TE's system is great, but for my money Factorization and Blood Magic are the new sleeper hits of interoperable and exciting power systems.
Seriously. Check out Factorization if you miss Blutricity. It reminds me of RP2 a lot.
Everything else is well covered by many other mods. Blutricity will probably never return.
And good riddance. Non-open power systems are awful. I don't care how beautiful Blutricty's model was. It failed fundamental requirements for a good power system.
