You can already do this.
Just put the kw's in a .txt file and use the Import function.
Then do Generate Keywords, Domain Check and Competition Analysis, and stop it whenever you want.
The keyword generation will add new keywords to the list but you can just delete this later.
As this came to discussion. I would also like to see some way to do that without the software generating more keywords.
I mean, importing the keywords from a txt file and on the settings putting something like a 0 levels to dig and the SW won't generate kw's but just analyze the search, competiton and domains for those imported.
Would that be possible?