If Mac OS X goes awry in the future, I'll abandon it. For now, it's my favourite platform. Unless there's a transactional instant where evil descends and alternatives go poof, I'm not too worried.
Its a long process of acclimatization, don't believe me? Take a look at android, which in most respects is far more locked down than any desktop operating system, yet is hailed as "open".
As long as I also have a proper computer, I welcome the simplicity of the tablet. If it looks like I will no longer have the option of buying or owning a proper computer, I'll join you with the pitchforks.
An ounce of prevention is worth a pound of cure.
It's a great argument for the anti-technology side because it seems to make sense to those that aren't technical, but let's not start spouting that fallacy on hacker news like it's actually true.
I would welcome more freedom on the iPad. If a switch showed up in the advanced settings that allowed side-loading of unsigned apps, that would be great. But it's not a deal breaker for what is a completely auxiliary device compared to a proper computer.
Ease-of-use in the real world is only partially a user-interface design issue, even though that is what software devs spend all day talking about. Turning on a device and being sure that no viruses are going to infect your computer, no malicious people are going to steal your email, and your device will probably just work is a giant ease-of-use feature. It makes your device easier-to-use when you don't have to worry about what your software will do, and that only comes when every single piece of software on your device comes from an authorized source that has been vetted by fairly reliable people who have the power to remotely fix problems on your device (for example, removing apps that turn out to be malicious). Don't kid yourself, even though you might disagree philosophically, removing developer flexibility is very much an ease-of-use feature for consumers.