In honor of you posting recognition of today's complaints, I've posted this using the beta. Even if some consider it pro forma at this point, here are some specific complaints:
1) "Oops! You do not appear to have javascript enabled. We're making progress in getting things working without JavaScript." Glad to hear it. No one should be "migrated" so long as javascript is mandatory.
2) White space and wasted space. Enough have made detailed complaints about this, so I'll just register my chagrin. I will say this: the people who come to this site are used to, indeed prefer, a denser presentation of information. This includes the text editor, which is absurdly restrictive on the x-axis.
3) Font size. Perhaps this falls under wasted space, but it's atrocious enough to deserve its own comment.
4) Incomplete summaries. Waste less space and use as much of the old summary as "Classic". (I recognize the drop-down menu allows one to switch between "Standard", "Classic", and "Headlines", but this, again, requires javascript. What is more, Standard adds nothing. Changes shouldn't be made for the sake of changing something. A change should be an improvement.)
5) Absurd margins on the right.
6) Obnoxious or irrelevant photos. We're literate here. Many of us read books that go on for hundreds of pages without a picture. We don't need pictures added like some security blanked.
7) Load more? The old system gave preference to higher modded comments but did not require that you filter for higher comments to see them. Of course when there are a great many comments, a load more button is useful. But such a button should not be obscuring high ranked comments within moments of an article being posted.

8) I just found another as I went to "Preview Comment." Why does the p tag produce what looks like four lines of white space?
9) Above all, all changes should be subjected to this test: Do they get in the way of the conversation? Do they make it harder to scan through the conversation, looking for interesting comments. If so, they are not improvements. They detract from the reason people come to Slashdot.
The formatting matters are some of the most obvious and often discussed. They should also be the easiest to fix.

If beta isn't stopped, it will be time to leave. Until that time, it's probably best to protest about it in shifts. Pick a time of the day to make your complaint known, then leave off visiting Slashdot for the day. Otherwise, today's protests will be just a flash in the pan. Constantly protesting is rather demoralizing, but it should continue until the beta is obligatory. Think of it, therefore, as a hike rather than a sprint.

Or better. They could require the use of Slashdot beta for all internet based discussion. Why ban speech when you can make it so cumbersome to follow that everyone will just give up?

Wow. One more thing. Clicking "Tour the New Slashdot", one is presented with the following claim:

A redesign 16 years in the making... you know it's going to be good.

Hey, I fell for that when I decided to play Duke Nukem Forever. I'll never get those 10 minutes of my life back. Fool me once...

That's funny. We used to have "user engagement." Now the engagement consists (rightly) in screaming about the beta. That gives an interesting spin on the stuff they're bragging about:

2.9 Million Monthly Unique Visitors [All of which will say WTF!?! when they make their monthly visit in February.]
4,653 Average Comments Per Day [Peaking well about this when it was announced that the beta was being phased in. 93% of the comments include the keywords "Fuck" and "Beta".]
93 Million Page Views Per Month [Past Performance Is Not an Indicator of Future Results.]

Indeed. About an hour ago everyone was complaining about OT downmods and making accusations. With the latest articles, it seems the Fuck Beta posts are being left alone.

[...] not quite as bad as Windows 8 [...]

It's built on the same design principle: If it ain't broke, abandon it for something entirely different.

Missing Option: Looking for work since my company shuttered. For some reason, everyone stopped visiting our website.

I doubt the moderators will be kind to someone who is so wrong.

Well, the users with mod points might not be kind. But there seems to be an unlimited supply of OT mods going about that are being applied to anti-beta posts. I'm sure the individual(s) doing this would be happy to supply some good karma to the turncloak.

It's a temporary home. Okian Warrior just registered it a couple of hours ago, so what can you expect? BTW, notice that my comment was downmodded OT into oblivion, even though (despite the snark) it was actually relevant to GP's comment? There is a disturbing trend here.

I've been posting here for years. I always try to be polite, even in disagreement. Accordingly, I have never been downmodded, except in a few cases of clear disagreement (i.e. a controversial topic gets "overrated", etc) and in most of those I generally get moved back to my starting score of 2 by others. I'm always at karma cap. Again, I ascribe this to the fact that the comments of someone who tries to be polite are generally not rejected by the community.

All this is to say that today is a first. I corrected a link to a comment by an AC here making it easier for folks to follow his intended direction to this project. When I did this, my comment was downmodded OT into oblivion.

I don't claim to know who's doing this OT downmodding, but if even my little comment (which was on topic for its GP) was downmodded then we should expect it to continue. Your comments may no longer be welcome on Slashdot.

Pathetic and ineffective? It's just a bad link. Here, I'll fix it:

Alternative Slashdot: altslashdot.org (thanks Okian Warrior (537106))