Does thinking small mean you're thinking smart? Maybe. Sometimes. It depends entirely on your priorities.
Scatter terrain is great for adding density and ambiance to a table. In skirmish-scale games, it's likely half or more of the cover you'll claim (and need to claim). In platoon/company scale games, it's mostly about visual 'flavor.'
Small pieces are certainly easier/faster to pump out, but blocking line of sight is, as mentioned, crucial in many rulesets. If you're in a gaming group and someone has the scatter covered, by all means focus on the big centerpieces. If you're flying solo... best to mix it up.
Having a vision for a given table helps, immensely. A blocked-out structure is playable, even if it takes you months to finish detailing it. In the end, you haven't sacrificed any game-time and will still end up with something to be proud of.
TLDR: Just build stuff. "Finished" and "playable" are not the same thing. As a 'planner' by nature, I'll vouch for the idea that 'done well enough' is generally preferable to 'immaculate, but 5 months late.'
[edit:] Well... I should have read the post on the blog before posting. I mostly just (independently, at least) parroted ideas you've already put forth. Whoops.