Question: Can the slow session launching be also the fault of the two Storefront's being behind a HAProxy, which is not supported (AFAIK) by Citrix? From the technical standpoint, can someone explain? This why I can tell the client.

No, I have my gateway behind one and it works fine. IF you RDP into the machine from name entry to launching an app is it just as slow?

Hit or miss. Sometimes yes, others no

So that sounds like it is a first time login spin up. Check Director for a breakdown of the login of the session, it will give a break down as to what part is causing the slowdown and you can address that. It is probably going to be, GPO, Shell, or Interactive Session that is causing the slow login.

Interactive session is what was longest taking

So that is the part of the login process from after the profile is loaded and the user gets access to the mouse and keyboard in the session. Check any services, programs in the run keys, AV, malware, etc that are loading before users get in, and see if you can move them to after the user is logged in with with things like WEM. How many seconds do you see it taking and we can compare it to other locations.

There's nothing running, not sure if any AV is even installed. Optimizer is ran as well. It's a strange jssuo