But there are upsides to death -- yes, lots of people die everyday, but death is fair since everybody dies at some point and death also produces renewal, changing the world for the better.
And I'm not saying that we shouldn't fix it. Heck, it may even make us less selfish; we may end up for example actually caring about our planet.
But in order to do that, there are more hard problems to solve first -- tyrants will be the first to achieve longer lives, capitalism will not work anymore, we need won't be able to have children, yes we do sex for fun but we also feel the need to reproduce so doing sex will be a lot less common, we'll have to work for all of our lives as wealth will become static, there will be no more entrepreneurs, whatever brain we'll have will have limited capacity so we'll forget meaningless details like our childhood (the happiest period of life for many people).
Even seemingly simple problems are actually big -- for example, right now death is fair, but what will happen after living 1000 years with your loved one until one day when she'll get hit by a bus? Then it won't be fair anymore and you'll most likely go mad.
And the biggest problem I'm seeing -- once the genie gets out of the bottle, it stays out. People need to at least make an attempt to fix these side-effects before solving death, not after. We cannot then say -- oops, this is was a bad idea, we'll just revert.
I've had family members die. It's painful, but at least you can live with it. And if the problems that I'm thinking about won't get solved first, I'm pretty sure that fixing death is a bad idea.