At the moment I would say that the text:simple filter is limited and you cant do very much to the text.
To make it more customizable I would purpose a Text Track (just like the video and audio tracks) to make you able to, blur, rotate, give drop shadow etc. I do know there are ways to do these things with the text but it would be much more straight forward with this track.
Probably will not happen. The reason there are separate audio and video tracks is for being able to mute and hide. Please learn about Open Other > Text. You can put that on any video track. Or, to make a text track, add a video track, rename it “Text” by clicking its “V2” (or similar) name, and add a text clip to it.