Luis.Santos,

You call it 'bad things'..... I do not agree with your definition, they are just non-features IMHO !

1. Balanced I/O is mostly important for microphone-lines to prevent electromagnetical-fields causing noise at the input of the mic-preamplifier.

For line-I/O however, it is slightly overdone to use balanced circuits if the line lenghts (instrument-mixing console) are short. I use inexpensive unbalanced cables from the SD1 (or any other board I ever owned the last 25 years !) to the mixing console and had never interference-noise on the amplifiers' output.
The use of unbalanced outputs is OK for me.

On the other hand you want a (balanced ) line-input on the SD1 ?
This makes me smile ..... this looks 'unprofessional' to me because a keyboard is NO mixing console but a keyboard.

A real Pro uses his mixing console and not the SD1 ..... ha !

The SD1 is not 'bad' at all !