Hm, to me it seems that you only use IC2 for its early game mechanics like ore doubling and such. That is not what other people complaining about here. And also, the IC2 early game mechanics are very easy to replace by other mods. Making IC2 machines require a hammer, a cutter, wires, plates, having to remake hammer and cutter when they break, and you have to harvest rubber. For Thermal Expansion, all you need to do is do your early game mining, find some sand and clay, smelt your ores, and make your machines. TE does not need little annoying fiddly parts, IC2 does. And you say you only need early IC2 power. You're clearly not using late game IC2 machines. The rest of us used IC2 to make UU matter to replicate stuff and to make Quantum armor. That requires a LOT of energy, so we have to make complex energy systems. And complex energy systems are hard to keep track of so one wrong wire = boom, your super expensive Replicator gone. That's punishing, and requires some pre knowledge of wires and such. And even for a veteran like me, I accidentally had two wires connecting and my Replicator exploded as well as my whole line of machines. People make mistakes, but they should not be punished like that in such a manner. TE instead makes it intuitive, if no power is transferring, obviously something is wrong. You try out different configurations, and you can figure it out by yourself. Try experimenting like that with IC2 and deal with a machine exploding in your face every time you try to figure how the power system works.Granted, I haven't gone far enough into IC2 to really know what the Metal Former is for, but depending on what you're doing, I'm guessing Mekanism will probably provide some substitute, which will be a lot easier to implement.
Again, Mekanism is the answer here. Truthfully, IC2's voltages were always something I considered a redundant nuisance, because there was virtually no use for medium voltage at all, and your machines always needed low. The power loss over distance was also always that high that for me it never justified stepping up and down, and laying cables over long distances, either. The best part here, however, is that you can still use IC2's machines for power generation, and then use Mekanism's cables for transport.
Like I said, for me redundancy is always a good thing. At the low end, getting started in IC2 still seems to be a bit cheaper than Thermal Expansion, and aside from the tiresome wrench mechanic, the machines have always been easy to set up and use, as well. If I've got plenty of rubber and the more basic metals lying around, and I'm in a jam, I can throw together an old school ore processing system very quickly, and I'm familiar enough with BC pipes (as previously mentioned) that using them doesn't bother me.
Don't get me wrong; I'm not suggesting continuing to use IC2 if you really don't like it. The new Metal Former and hammer/cutter tedium notwithstanding, however, IC2 does still seem to have fairly smooth, easy progression for the most part; it and Mekanism are truthfully still a lot less tedious than the molten redstone tier for me is with Thermal Expansion. I truthfully don't bother going past TE's basic liquiducts and item ducts; the infrastructure for them is simply too painful, and I can get what they would give me in other ways. I also don't actually like "smart" piping so much, because virtually none of the new systems with linked state routing, still have the level of fine grained control that RP2 did, and TE is no real exception.
Again, I'm not bashing TE here. It also has its' uses. The Autonomous Activator in particular is invaluable for me. It's just that I find that what I tend to do, is build a bit here and a bit there from a lot of different mods, skip most of the really painful stuff, and then lean on Mekanism as a bridge system for tying it all together, and the old BC pipes for transport. It's ad hoc, but because I don't play SMP, it works extremely well.
And we also discussed that the late game IC2 is also very subpar. You have to make machines to make more machines. The Extractor is practically mandatory because cooking 1 by 1 rubber seriously sucks. (The Metal Former btw sucks, because it's slow as shit, and you need to make Overclockers for it, and btw Overclockers are seriously annoying to make). The Quantum Armor is replaced by the awesomely utility epic Modular Powersuits. The tools are replaced by Tinker's Construct to the extent that you don't need to bother with a drill. The only really good thing is the Induction Furnace which is why I go through all the IC2 trouble for it, and I'm pretty sure that there are other mods with super fast furnaces.
You also state that you know how BC pipes work so you don't need to bother with all of the TE stuff. Well, what about for a beginner? Not everyone starts out with a full knowledge of BC pipes. And they're obscure to the point where it's difficult to figure stuff out. Even now I'm still confused with some of the pipes but that's because I've never really had to use BC ever. TE pipes are easy to play around with and figure out. Also, TE pipes look so much better and only require some early game mining to get the opaque versions. No glass needed.