I would like the possibility to load templates in the step sequencer view, in order to be able to save/recall settings to match some drum machine programs, scales, etc.
for example, in some cases i need just drum,snare,3 hats and a couple of cymbal. i would like to save/recall a preset with just 5 tracks already assigned to predefined keys.
 
also, i may need to make an arpeggiated synth line in the key of G major. so, i would like the possibility to either save/recall a scale with just the note of the G major scale OR the possibilty to auto insert all the relevant notes of a particular scale.
 
EDIT - another request: it would be nice to have the possibility to get the image of a keyboard in the left panel, instead of the notes. similar to the piano roll view

Step sequencer templates already exist. SONAR bundles a few in the "Step Sequencer Patterns\Templates" folder. Configure the step sequencer as needed as save it as a pattern.

AH! 
did not know about it! :)
will look it soon
 
 
another request: it would be nice to have the possibility to get the image of a keyboard in the left panel, instead of the notes. similar to the piano roll view

bosone
in some cases i need just drum,snare,3 hats and a couple of cymbal. i would like to save/recall a preset with just 5 tracks already assigned to predefined keys.

 
You can also create and save a drum map.  When you apply that in your MIDI track, the Step Sequencer will open with the individual instruments already assigned.

You can make a midi clip via the piano roll then convert it to step sequencer to solve your second request.