Powerful yes, well used no. Lemming always said it could have tiers, but it never did past transmission limits. Suddenly Thermal Dyanmics comes and even that's not true anymore with infinite RF/t conduits. As for intuitive, coding wise it is (or was the last time I looked) a lot more simple than EU and indeed MJ that it replaced, for the end user it's down to how the mod implements it. You could do an IC2 style exploding if too much RT/t comes in but with conduits that can carry so much power you'd most likely be forcing the user down certain transmission methods, oops there goes completely intuitive. This is where floaty comes in, it doesn't have commonly divisible production values, so having tier based machines is very hard to achieve while still going with the RF trait of working well/integrating with other RF mods. Flexible is totally true, the range of RF using mods shows that. There is plenty more that could be done with RF though that hasn't been, and might never be able to at this point because of what is already there.
Yep, but that should just be a FTB problem. Look at Immersive Engineering for instance, If it was added to say Infinity I don't see a lot of it's features being used. Water Wheels/ Windmills might be used for early power, MAYBE a bio diesel generator if they don't want to opt for the more compact MFR rout. Belts wont see a look in because the mod works perfectly with ducts, the drill only goes 2x2 most will opt for a TiCo Hammer, The grinder as cool of a beast as it is only doubles ore and costs so much steel making 2x ore a post nether thing due to the blast furnace requirement, most will opt for a SAG mill or Pulverizer.
But if you look at it from a custom perspective there is no problem as you can make a pack where Immersive Engineering center stage, by omitting mods like EIO and TE. you can even use Minetweaker to buff EI or nerf EIO and TE.
Using IE as an example I don't think the stuff we have now is getting in the way of new innovative use, it's players insistence (or hard requirement due to multiplayer) on using standard packs and modders adherence to those packs balance paradigms.
Essentially what you are saying is that modders could do something clever and balanced with RF, but would rather not bother becasue they know their design wont be preferred over an easier/ more efficient option in the popular pack.
Even Modders who cut against the grain are guilty of worrying too much about what happens in packs. Reika for instance worries way too much about what other mods are doing/ interacting to his. Becasue he knows that if his mod shares a popular pack with said mod/s he'd be forced to conform to the standard or that players might find certain exploity mods to be considered requirements for use of his mods.
He can't be faulted for it either, 90% of players experience mods via large public packs if a mod interaction ruins a mods mechanic that's going to be perceived as the proper intended balance.
I think if we empower the player to customize and easily share their mod packs this in turn will empower modders to march to the beat of their own drums. We'd see more Immersive Engineerings and RotaryCrafts being made as they don't have to worry about how their design fit in to XFTB packs balance dynamic.