I like the second idea a lot.  I would want to use it for nearly all my Terraforming choices.  By the time I start Terraforming, I usually know exactly what building I want that tile for.  I reduce the micromanagement a bit by delaying the Terraform techs and then getting the whole branch researched all at once.  I go through one pass of planet management on a giant empire with all the terraform projects, and then, as each one wakes up again, set the buildings.  They don't all finish Terraforming at the same time and the second pass is very annoying as you have to tend to several planets per turn.  This would reduce all that to one pass, ending up with planets full of buildings at the end.  Sweet.

But I wouldn't want to guess at it earlier than actually doing the terraforming.  I change my mind about things too often until the moment I force myself to put a decision into a build cue.  Situations get too fluid.  I get too indecisive.  The consequences get too important.  What if I lose the whole Galaxy because of this one choice?

What annoys me the most about land improvement is having available low level improvement and planet refuses to let me use it!

But yea, getting multiple land improvement techs before using is handy because then you can preview what its allowing for the more advanced techs and that helps you decide what to do with the lower level techs. Sometimes things you would expect the higher level improvement would allow, inexplicably it does not, and you like 'DOH'