I think virtually all titles are ripe for a knock down price, at some time down the road. This will be no different, it will fall in price at some stage, probably if/when they have come out regards updates. If they have a big content update the price won't move much for a while. If it seems that the next update is going to be a final one, for some reason (hopefully not), then the price will fall quite a lot, I guess.
But this game, if your into exploring, is worth every penny. Well certainly for me it has been, I love exploring space/planets, this is more for the planet side which is agreed. But that may also change if they choose to flesh out the space side a little more.
Exploring wise, nothing quite like it.
Regards worth it.. I say 'for me'.
But I have to say, it comes down to what you want to spend, or indeed can spend. If you don't want to spend that much, simply wait, more or less everything drops in price as time passes. I bought into ED for £150 way back, so its @ £19.99 now on Steam. But I still wouldn't have waited for that price drop. If people want things, they tend to spend on them. I do...
It goes for many games I own. 'Early in', doesn't always mean saving later...