The Tardis crew get cut down to size, literally, in the ‘classic’ Series 2 opening story Planet of Giants, the first story to get the HD Re-classic-ation treatment for quite awhile (at least as executed). And the contrast between this story and the last story which the Tour capped, The Church on Ruby Road, could scarcely be more stark.
The history of classic Doctor Who have more examples of stories being expanded, like The War Games, to compensate for other stories which fell through at relatively the last minute, or being ‘written over a weekend’ like The Invasion of Time (where the cumulative effect made it seem like the story took forever) than stories which were reduced and tightened up because it was thought it would make the pace of the story work better. The Dominators was cut from six to five episodes, and the authors took their names off the story as a protest.
Planet of Giants went from four to three, and watching it reveals why. The Tardis core four are, for reasons both small and smaller, in their own little universe. Thus their story is only of them talking to each other in various combinations, all close-in as was often the style at the time. A necessity, but one which doesn’t do much, outside from the large scale props, to intrigue the viewer.
Whereas Planet of Giants was small in every intended detail, The Church on Ruby Road was big, grand, and expansive, a revelatory bit of contrast coming one after another. Now if William Hartnell had broken out in song in Planet of Giants, that would’ve been BIG (not to mention extremely odd).