Do you really think one-by-one story estimation is that bad? At Kongregate it's about 8 people doing it, for 45 minutes or so every couple of weeks. It isn't the most fun thing in the world, but I do think it's helpful to spend between 30 seconds and a few minutes talking about how hard something's going to be. If it seems hard, easier ways are often suggested...
If you're not looking at them one by one, what are you really doing? Why not just say all stories are the same difficulty?
The planning meeting isn't the right place to review the implementation approach of every story. That's best left to another discussion among the technical team, probably in a design review.[1]
Discussion isn't necessary for estimation purposes when the team agrees on effort. It's only necessary when the team can't agree where to rank the story's effort in relation to other stories, both completed and upcoming. (You need completed stories in there to "anchor" the story points, otherwise the meaning of a point will drift from iteration to iteration.) Once the team has ranked most stories, the team can return to those that they can't rank, and discuss them a little further until they can fit them into the rankings.
[1] It could be that the team isn't communicating enough, and that the planning meeting is the only time they're forced to communicate.
If you're not looking at them one by one, what are you really doing? Why not just say all stories are the same difficulty?