Ok, you need to redesign the site.
We get it.
Anyone who has tried to read the comment threads on an iPhone gets it. Slashdot didn't make the transition to the separation of content and display well, limiting your flexibility when it comes to adapting to the plethora of new devices popping up. Among other things which I'm sure include "monetizing" the site more.
So, you need to redesign the site. Got it.
So, you created "Beta", whether because of an edict from the new corporate masters or whether it's an internally driven project, it was immediately obvious whoever did Beta ( on mobile especially) didn't even do a basic "This is how people use the site" survey. Or if they did, they did a really shitty job. Maybe they read the comments and thought those were the truth. Anyway.
So, here's a thought:
What if you did the redesign in an open/community driven manner?
Set up a persistent discussion (make it a tab, "Changes are a coming to Slashdot", weigh in with a comment) and explain what changes you want to make, and why. Let the community hash it out. Maybe let us vote on a feature, and allow us to test it out on some dummy (or real) stories to see how it works. Allow us to view different stories under the new look and layout. Maybe with a button that changes the CSS a la CSS Zengarden (simplest reference site) or that redirects us to the same story at beta1.slashdot.org, beta2.slashdot.org, etc if it requires serious architectural changes that can't be done with just a reskin. Or something similar.
Also, set up a persistent discussion board where you guys explain the issues you're trying to fix and why(!) and see what the community has to say. You have one of the largest dens of geeks of varying skill and knowledge levels on this site and it's quite possible they may have an actual solution for you, or a simpler one, or a better one. I know the guys who run slashdot are super-geeks, but you can't know everything (root != god, sorry). But the community has an incredible amount of combined knowledge. Use it. And read the comments at level 1 or 2, since the way the slashdot moderation system works, a lot of valid commentary will get pushed down over the most artful use of an obligatory xkcd Natalie Portman reference.
Then, instead of committing to wholesale bulk changing the site (come on, you have to know better. Who's forcing that on you? New management? Tell them what's up.), make incremental changes. Maybe to one set of features of a subsystem, or an entire section or something. If that section of the site is "Difficult" to fix because it's interwoven with other parts of the site, then spend the time to unravel it. You're going to have to anyway.
But regardless, instead of making bulk changes and driving away the people that allow this site to make enough money for it to change corporate hands a few times, include the community. Maybe we'll have feature suggestions you didn't even know about. Maybe we'll have a solution to what you thought were inexplicable problems that are easily solved because you're just aware the solution exists. Maybe you're agonizing over a feature no one uses.
But try including the community. And it's a community, not an "Audience". Nor are we users. We're a community. Of people. Online. If you need to spin it for the new corporate overlords, we are the biggest "stakeholder" in the redesign. Frame the problem that way on the whiteboards and in the meetings with the IT people.
The beta and redesign comments have spilled into way too many comment threads. Because you guys are clearly managing it poorly. Or someone from corporate is managing it poorly. You've got once change to do this right. Because if you drive the community away, like the former inhabitants of Chernobyl and mySpace, they're not coming back.
Maybe it takes a little longer than it should. Unless you've got some corporate budget target to meet, that's ok with most of us. If it takes a year, or two. Who cares if it results in a truly better slashdot? Put Classic into maintenance mode. Most people will understand. And turn beta into something the community had a hand in.
I'm fairly certain the community isn't actually resistant to change (regardless of what the comments say), we're resistant to shitty change.
So make it not shitty.
By including us.
See what happens.
The worst that can happen is it'll get modded -1 Flamebait. :)