I have Alivio on my '96 Jamis Durango (7 speed) and it's been zero maintenance (aside from the natural wear items). Low end doesn't necessarily mean poor performance.
I'd just go ahead and replace the cassette and the chain.
This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.