Several sequencers have added some notation capability but they often will only show one instrument at a time and only a few measures at a time or the MIDI data is severely rounded off to make the notes look nice but this causes the notation not to reasonably display what you intended to convey. This solution is usually incorporated by people who have spent years using only piano roll, often can not read music very well and are not in a habit of considering what all the other instruments will be doing when they are composing for any one instrument. Essentially they don't know how to use musical notation so they don't miss its absence and are not capable of understanding how it must function within a sequencer for it to be useful to a composer. Some of those programs are gradually getting better in fits and starts but I am happy to say that a few sequencers have been much closer to the mark all along. Specifically Logic by Emagic is a program which used to be called Notator and has had the right idea all along starting on the old Atari computers.
Logic is an extremely complex and powerful program.
Emagic hates it when you say that Logic has a steep learning curve. But this program makes even a steep learning curve worth the effort. Fortunately most people using Logic today have used it for years and are comfortable with it by now. My old favorite is Musicator GS for DOS which, though not very powerful, has an extremely musician friendly layout. Musicator GS for windows in now in its 3rd generation and incorporates digital audio but some of the key features were dropped when they went from DOS to windows and they are very slowly being re-incorporated into the program though it is now much more powerful in many other ways.