I think step sequencer desperately needs the ability to zoom in/out to fit longer patterns on the screen without having to scroll. After doing a search it seems that quite a few users would like to see this functionality as well. It seems like it would be a pretty simple function to implement and would make the step sequencer so much easier to work with.
It would also be handy if the indicator/marker in the step sequencer let you know where the "Now Marker" is positioned in relation to the project even when playback is not active. For example, if I move the now marker to measure 2, beat 3 in the project, and there is an active step sequencer pattern in that region, the step sequencer should also show me that I am positioned at measure 2, beat 3. As it is now, the current indicator only moves when playback is going, which can be hard to follow along with when you start to get into more complex, longer patterns with very small note divisions (i.e. 1/32, 1/64, etc).
Just a few things I noticed while trying to use it recently for some drum parts. The step sequencer is a tool that has so much potential and could really be great with just a bit of fine tuning imo.