The question is, do you disagree with how the rule works, or with how the rule should work.
Like I said, I don't see the power imbalance that R&D supposedly perceived. To me, at least, the Feat's silence is still is open to interpretation, and I'll continue to rule it to function identically to Expanded Knowledge.
IMHO, the Full casters & Full manifesters are pretty balanced versus each other, even with the FAQ interpreting Extra Spell and Expanded Knowledge differently. Others on these boards have vociferously voiced opinions that the Psionic Classes routinely outdo the Core casters.
Combine that with the differing interpretations of the Feats resulting in the lesser manifesting classes getting access to all the Psion/Wilder list while lesser spellcasters getting shut out.
In reality, its not the difference in the number of powers vs number of spells available to each class, its the difference in the quality of the powers vs the spells that have most people up in arms.
Most people on these boards who play min-maxed full casters routinely have a mental list of spells they will almost always take for those PCs. And judging by the number of times those spells show up in threads helping newbies out for their wizards & sorcerers, or complaining about overpowered spells, I'm pretty sure those PC spell-lists would be 80-90% the same. That's the same 30-some spells out of 1000 WotC spells, chosen again and again, all around the world. Pare the list from which to choose down to Core + Completes, and the spell lists would become even more similar. If the selection was Core only, I'd be willing to bet you'd see 99% or better identity.
I'm not sure the same could be said of min-maxed Psions and Wilders, despite a much smaller pool from which to choose.
Clearly, the Sorc/Wiz list has a lot more "dead weight" on it.
Yet this is precisely the list that is being the most restricted, and because of this, the so-called "underpowered" partial spellcasters like Bards, etc. will forever be even worse off in comparison to the lesser psionic manifesters than ever before, lending creedence to the complaints of those who believe the Psionic classes are overpowered relative to the core spellcasting classes.