Well, you could:
In the auto completions file (AutoHotkey.sublime-completions) in the AutoHotkey package, you can add your own auto completions.
However you could modify the #IfWinActive line to be: {"trigger": "#IfWinActive", "contents": "#IfWinActive${1:, [ WinTitle}, ${2:WinText]}$0"},. So when you add the directive to your script you could just press enter and it'll overwrite it and remove the extra parameters.
On a side note:
The Sublime Text AutoHotkey package is kind of underdone and slightly outdated. I'm currently working on updating it and making it better overall.