I believe I've asked this question before, but in the chance that asking it again will prompt some conversations at Balsamiq headquarters, I figured why not!
I'm really missing the ability to lay out grids/guidelines in Mockups 3.
Mockups is for the fast creation of wireframes, no doubt, but a grid is almost the first thing a designer decides upon, and a grid/set of guidelines is very important for a design, even at the wireframe stage.
The current guideline system often frustrates me - it's hard to tell which item you're aligning with, the light gold guide line is often indistinguishable from the light grey guide line, and the feature doesn't help to layout an overarching structure.
If I want to create a grid of 50 pixel wide columns, with a gutter of 10 pixels between each, the only way I can do it is create a bunch of rectangles on the page, which I then need to go back and delete or hide after the design is finished.
Is there any hope for a grid/guideline system that helps users to make macro layout decisions, rather than the current guideline system which focuses on micro layout decisions?