1. Thanks! That's exactly why I was curious, since I saw the "next version".
I suggest sending feedback in that article, to ask exactly when will that option be deprecated.
People have been using that capability for a long time to have a "low touch" way of accessing a mashup, without requiring an authenticator.
2. The Custom Authenticator is not really a complex thing to implement, just that you need to have some training in it, and I believe one day should be enough if you have some Java experience.
Regarding the "SIMPLE" programming: ThingWorx as a platform has lots of capabilities, but, as with any platform, I hope it is obvious we can't offer absolutely anything in the platform.
Therefore, we created the ThingWorx Extension SDK, in Java, to give people options to extend the platform capabilities as they need for their use-cases, giving access to low-level platform capabilities than what's available in Composer.
Typically in 99% of situations, in ThingWorx there's no need to use that Extension SDK and you can use the platform capabilities, just that in this situation you need to go at a low level.
I personally recommend self-training or locating resources with Java knowledge, because there are situations when the systems you want to interact with can only do that via third party libraries (offered as Java JARs). What I mean is that in some situations you need to use the Extension SDK or Java, and there's no way around that. Again, to be taken as thing to keep in mind and not reject this option automatically. This should take, again, less then 1% of your total dev time.
A third option that some customers use, is to have ThingWorx setup in SSO mode, and there's one very specific configuration I've seen for customer that makes that each time when they access ThingWorx instance, they are automatically authenticated as their Windows user (with no auth window).