If you get max for live there are a load of step sequencers available. Otherwise you might have to download a third party vst to use.
Hey I see something called "Mono Sequencer" in Max Live. Is there a way to get that by itself??
Not really, if you could get M4L devices to work without M4L, it'd be pretty bad for the business of trying to sell M4L
But could you elaborate a bit on what/why you want something else than the supremely versatile Drum Racks and/or Impulse and just using the piano roll? Wanting simplicity is a good enough reason for sure, of course. Just trying to make sure you're not asking for something you already have...