Yes, in many ways you are right, the idea of there being a "heaven on Earth" doesn't really make sense to me either, but I guess its meant to imply that we can get closer to a state devoid of suffering if we put our mind to it, rather than waiting for an afterlife.
To be honest, I'm a hardcore pessimistic nihilist, so I feel intense sadness at the way the world is - the kind of evil and cruelty we see around us - and regardless of there being a better state we can achieve or not, what makes me weep is the state we are in now. Its not my life so much as the life of those less fortunate around me that makes me despair, regardless of whether there is a purpose to all this suffering or not. The fact that we have to go through such ups and downs in the first place seems pointless to me. Why not just get rid of free will and sentient beings, what's the point of us having been created in the first place? I don't get it.