Hello
there is a simple way to change the Keyboard (the input method) with tasker:
the Plugin "Secure Settings" which is available in Google Play (for free).
E.g.: I have some Apps where the predictable way of keyboard is not useful (ConnectBot, Terminal Emulator) and to avoid of changing each time to the "Hackers Keyboard", which is much better here, I have:
Profile "Hackers":
Application / "Terminal Emulator", "ConnectBot"
Task "hackers":
Plugin / "Secure Settings" / Configuration 'Edit' / Helper Actions / Input Method: Hacker's Keyboard
To get the "normal" Keyboard (I use Swype and Swype Beta) I have the same kind of Tasker Profiles for other editing Apps (like WhatsApp: Swype Beta, Evernote: Swype, k9mail: Swype Beta, Jota+:Swype etc.)
Hope it helps someone.
franc