Hello Otis -
Whether a plugin or a standalone, both require downloading and installing a copy of the LiveCode engine. In both cases the actual stack files the user interacts with can be easily downloaded at runtime from any web server, so you can update them at any time and the user always has the most recent build automatically.
A standalone has the additional benefit of being able to provide a UI dedicated for your app, in contrast to a browser designed for web pages in which things like "Go Back" have no meaning in a plugin stack and can cause data loss.
Standalones can also be more secure than a plugin. While both involve compiled proprietary code and therefore the user can never be completely certain it's playing by the rules, for users that trust the app's maker enough to install the engine a standalone offers a secureMode global property which is even more restrictive than the limitations of a browser plugin in terms of modifying locally-stored data (secureMode prevents all local storage, even things as small as cookies).
And if your audience trusts you enough to allow local storage, you can craft your own smart caching to support an offline mode, something that's not possible with most plugin implementations.
With all the benefits of standalones over a browser plugin, I think you summed it up well when you wrote: "It is a technological barrier as well as a psychological barrier."
Technically, it's equally simple to run an installer for a standalone as it is for a browser, and arguably simpler for you to deliver stack files to it over the web since they don't need to be converted into a plugin-compatible format.
But psychologically, you're right on the mark. Many people *believe* that browser plugins are somehow more secure and simpler to use than a native app, and as long as such beliefs exist they must be addressed in conversations with relevant stakeholders.
In most cases a review of the actual benefits and limitations of standalones vs. browser plugins quickly helps stakeholders acknowledge the benefits of the former.
That said, there are some cases where a plugin was never truly what the stakeholders wanted, but didn't fully understand that they require installation just like any other compile code. Many want a solution that "just works" with the software they already have, their browser, and they didn't think it through far enough to realize that a plugin doesn't really provide that, that they'd still need to install some compiled object code.
In such cases where no LiveCode engine -- either standalone or plugin - would be an acceptable solution, you'll have to consider JavaScript driving HTML instead of LiveCode scripts driving stacks. The great thing about using JavaScript is that you don't need to spend a lot of time evaluating alternatives: as the only scripting engine included with every browser, we have no choice in the matter.
One nice thing about the Web is the ubiquity of tools available. You may even find a site that offers services close enough to what you need that you can use an off-the-shelf solution.
And if not, JavaScript is only getting ever more important each year, so it's well worth the time spent learning it. And as Sean suggested, some stack layouts can be translated to CSS with relative ease.
