- no need to install any huge packages/libraries/devenv in order to modify elements of the GUI
This is solved by writing a native, not a browser GUI.
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- easy to setup remote access to the GUI
When do you need it and what about security implications?I really don't see it as a problem.
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- the ultimate platform independence (no wx, no other qt will give you that)
- the ultimate browser type and version dependence.Quote
Slower response times matter in any kind of application. They affect subconscious feelings of the users - how they feel about the application.
Sounds like you are a real expert in this domain - I'm not going to argue here. 
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You can limit the GUI to accept connections only from localhost.
...making it easier for any malicious, especially browser-based, viruses to interact with the client. I am not sure, but what if the user opens a README for some program that contains an AJAX javascript to interact with the GUI? It will be accepted because it will come from localhost.I really don't understand your security concerns. Don't you use internet banking?
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Debugging of HTTP/JS apps is easy.
Ha! Why didn't I know this before?! What a fool I was spending countless hours, trying to make something look and work the same way in all browsers...