I started work on Pro version of BTTerminal. This version will be paid with similar price tag as cheap Arduino Pro Mini clone 
What are planned features :
- sending non ascii characters into device with simple escapes like \r \n and also full \xFF escape characters
- devices can be pinned to desktop so you can connect to device with one touch on Tile
- saved devices will have capability to send initial pack of characters to device (like two times CRLF to switch into command line mode and so)
- robot control keyboard – instead of standard keyboard can be robo keyboard activated. 3×3 buttons keyboard will be displayed with capability to remap codes sent by terminal to robot. Also you can say which button is visible or not. Feature can be used to drive robot with arrow buttons and fire Nerf mounted weapon with middle button 
Or just send another 9 codes into device with fast access and without typing codes.
- Universal App version will be available soon – will run on WP 8.1. and Win8.1 (pay once, run on both) with additional features delivered with new SDK, including Cortana integration so you will be able start your communication with voice command. This version will be released after WP8.0 Pro version.
Original version of BT Terminal stays free and without 3rd party ads. I will put there only small, not disturbing ad to BT Terminal Pro.
Let me know what do you think or what do you want to add into app.