I wouldn't say it was an absolute lack of planning, and if you felt they stuck the landing, awesome, but when I wrote that, I was thinking back to
an interview with Ron Moore from when the show was just about to wrap up. There will inevitably be stuff that writers figure out as they go, and in many cases those are things that end up working beautifully, but I didn't find it encouraging when Moore says that one of the crucial plot twists in the series, with far-reaching ramifications, was something they came up with essentially on the fly in the writers' room to add some gravitas to a season finale.
Also from the link:
Q: One of the things I find interesting is, on "Lost," Cuse and Lindelof have always claimed they have a master plan and know where it's all going, and fandom has been skeptical at times and said, "Yeah, right." Whereas you've been pretty candid about the fact that you'll throw stuff out there and figure it out later, and yet people assume there's some cohesive plan to "Galactica." How do you pull that off to make it seem like there's a plan?
A (Moore): To me, that's the job. The job is to figure a way along in a story but make it all feel like it's seamless, to make it all make sense. Hopefully, if I've done my job right, when all is said and done and the story's been put to bed and you've got the entire set of DVDs before you and you watch them, that it feels like a cohesive narrative -- that stuff we just threw up and decided to take a flier on without ultimately knowing where it would pay off, when you look at in hindsight, that it all tracks. You're painting this large painting on this big canvas, and you may not know what it's going to look like at the end, but when you're done, you want it to feel like it's a cohesive vision and makes perfect sense.