My conclusion is that you change your monitor far less often than you change your GPU. So when you do, you need to aim high.
I consider 1080p to be effectively dead now. It will be around for a while, but I don't see it as a worthwhile investment. Far better to get a 1440p if you want to upgrade. Sure, if your today 1080p goes fizzle and you need to replace then another 1080p isn't going to be a backward step. If you're planning an upgrade, then you should make sure it is an upgrade.
There is an argument that going from 1080p 75hz to 1080p 144hz or greater is an upgrade. It is, but I'd question if its an worthwhile one over going to 1440p at 144hz.
Oh, and OP - you're 1070 will be fine with either 1080p or 1440p, but if it was me I would be looking for a 1440p with the highest refresh rate, at the best price.