Hi Tripplecad, I do a lot of electrical as well and use symbol blocks with text attributes. All of my attributes have a preset value which is the default value and is changeable after insertion. The settings I use for all text attributes are:
Invisible = OFF
Constant = OFF
Verify = OFF
Preset = ON
Value = the default value I want
My original symbol blocks were made in Acad 2002 and when I insert (copy) them into XT, I cannot modify any of the block text attributes (they are all grayed out) until after I save the drawing, close it and then reopen it. For compatibility reasons I always use the DWG 2000-2003 format when I save drawings. In XT V1 I had noticed that if I didn't use a preset with a filled in value, that I could not even see it in the XT property dialog. To get around this, I always make sure the value is never left blank when defining attributes. True XT has some quirks when dealing with attributes but it is possible to get it working like you want.
One other issue you may run across is if you have attributes in your title block and have already placed multiple title blocks in paper space. If you then try and edit the master title block and save changes to the block, the copies in paper space may not reflect the changes. To fix this, delete the block insertions in paper space and then re-insert them using your modified title block, then all your changes should be present.
Also once you have a block in your drawing, don't try and use <ctrl> C/<ctrl> V to copy it as XT will then ask you if you want to replace the original block. The regular command line COPY works fine though...
On the plus side, mirroring of blocks with text attributes works as expected in XT where as in Acad, the font justification was all screwed up.
I too am eager for enhancements in this area, so good luck all around!