Jewish Renewal is not, as you seem to assume, about "having all the
answers," or even about being "right" at all. I have several points to
address:

"I am even less persuaded by the equation that old = bad and new = good"

Creating a good-bad, us-them mentality is exactly the sort of thing
that Renewal encourages us to avoid. The idea of "progress" is not
inherently a "good" or "bad" thing. It means change, and the world IS
changing. People themselves are changing. The issues we have to deal
with on a day to day basis can be so different from even 10 years ago, or
more, with the advent of new technology, etc. etc. This is certainly
not a new idea. Renewal is dedicated to using the current vocabulary
and current expressions of things that are, as you say, old ideas. It
isn't about being the first to say that other religions reflect truth;
it's about continuing to say that. To say it in the most up-to-date and "progressive" way
possible. That doesn't make anyone better or worse than anyone else.
It's simply the Renewal approach.

As far as triumphalism, and believing the new to be "better" than the
old, I believe I've already started addressing that. You say: "There is
arrogance in believing that 'new' is always 'improved,' that one is
always more intelligent or on a higher moral level than one’s elders or
ancestors." This is very true. I don't see any place in Rabbi Waskow's
letter that indicates such a position. In fact, he appears to be making
exactly the SAME point. Jewish Renewal "affirms," it has "insight," it
encourages "humility."

It isn't about reinventing the wheel. It isn't about abandoning
tradition in favor of fads. In fact, Renewal is specifically NOT a
denominational deal. I have personally met people involved with Renewal
who are Orthodox, Reform, Conservative, and even those without much
knowledge or affiliation at all. Renewal isn't trying to replace
anything.

Lastly, you say this...

"Even when we choose to dispense with a particular tradition, the
process of religious reevaluation must be grounded in knowledge of what
is being rejected. Before one can 'think outside the box,' you need to
know the contents of the box."

...as though first of all Renewal exists to undermine tradition, and
second of all as though those involved with Renewal are in some way
inherently ignorant of past traditions. This is simply not the case.
Every single facet of Judaism, every single movement or denomination or
group, contains people who are knowledgeable and people who are not.
Renewal, Reform, Conservative, everyone. I'm not completely sure what
you're trying to say, but I am curious.

If you mean that people should study as much of the traditions within
Judaism as possible, I certainly agree, and so does Renewal. If you
mean that those who dismiss tradition without fully understanding it
are missing out, then I agree, and so does Renewal. Renewal encourages
understanding, and learning as much as you can, as much as you want.

If, on the other hand, you mean that there is some kind of minimum
knowledge requirement to make spiritual decisions, then I'm confused.

In summary, I think your biggest misunderstanding is equating "new"
with "inherently better." Renewal doesn't make that claim; it's
unfortunate you think so. Renewal supports the idea of everyone trying
to better themselves, become more conscious, of keeping spirituality.
Being the "first" to do so or not is totally irrelevant, and as you
said, arrogant. If Renewal was about being the first to achieve
anything, it would be fundamentally contradicting the tenet of
understanding and humility that we all continue to pursue.

I should also say that I'm not a Rabbi, or even a real scholar; this is
all from the years I've spent observing and becoming involved with
Renewal. I'm not trying to advocate Renewal as a spiritual panacea, or
bring people into the fold, or something like that. People can become
involved or not as they choose, at any level they wish. I just don't
want to stand by without adding my perspective, especially regarding
the good-bad thing.

~ Sarah Beck-Berman