Notice the mods that have nerfed things? Now tell me which mods in a big pack like monster get the most use and fame, and which ones get people complaining?
If there are a set of mods in a pack, and some mods decide to nerf themselves, you can't call the rest of the mods staying the same "Power Creep." That's actually the direct opposite of power creep.
To me you wrapped up my whole theory with your post. Every nerf we have seen gets constant complaints, and people are always, always posting things here like 'BC is just behind the times, TE3 is what I use for everything now". "I only use railcraft for the boilers".
Im sure you can say that you and other veterans have done so, but you have to agree that for the average player what i say is true. You did not mention ONE NERF that referenced Thermal Expansion at all, and it's the most popular mod out there. Every mod you did mention gets a lot of flack or is less used than other options. Forestry is not really referenced either way and suprise surprise... defaults to 'easy' mode.
The point here is that people were comfortable the level of power from the mods in 1.4. It fit the playstyle of a lot (i'd say most) of people who choose to play modded minecraft. When a mod designer decides to nerf his mod so that it doesn't fit that playstyle any more, it shouldn't be a surprise that people choose to use one of the myriad other options available.
Yeah, I don't use BC pipes any more. I've always avoided them as much as possible, except for bees. Before TE itemducts, I used RP tubes almost exclusively. Or logistics pipes when tubes weren't quite right for the job. Or, if there were no other options, often I'd just do without item transport at all, and move stuff manually. BC was great for machines like pumps, builders, fillers and the integration with forestry, but the pipes have always kinda sucked. They are getting better though, and are in a legitimately useful state now, but there are definitely things that can be improved about them.
And yeah, I only used Railcraft for the boilers. Cart systems are ok, but aren't the most important thing to me, and a lot of the fiddly bits from Railcraft with having to make blast furnaces and use rolling machines just has never been worth it for the benefit. I used to make train systems in vanilla to connect my various spread out bases. I stopped doing it in modded minecraft because the expense of making the rails through railcraft wasn't worth the time it would take to just walk/fly/ride there. I was finding that by the time making the rails became trivial, I'd have teleportation available with mystcraft or thaumcraft or portalguns or some other mod and wouldn't need a rail system any more anyway.
I'm not saying I haven't tried these things. I have. I've tried most of the various items in most of the mods in the FtB packs. But I don't keep doing stuff that isn't either fun or useful. And generally, I don't find frustration or tedium fun. If something gets tedious enough, I'll just do without, or do it the vanilla way. For example, if the only option I had for automated farming was Steve's Carts, at this point, I'd probably just do my tree farming with a lumber axe and fuel my base with lava. And if the only option was Forestry, i would HAVE to because I need a power infrastructure just to get the multifarm in the first place.