Johannus said:

Rather than imagine replacing Yoda with another small character wouldn't it be easier to replace him with a character witha large silhouette. For example a different small character could involve masking Yoda out, then replacing the background and adding the new character in. Or just carefully matching the head angles and masking and replacing just the head (and recolouring the hands or something). Whereas if you had a human sized character with a wide cape you could just cover over Yoda in most of his scenes. This might involve rescaling certain shots and backgrounds do to the height change, but overall I think it would be less work.

My point about simply covering him up with a larger character is that it doesn't work. The angles are all wrong. In scenes where Yoda is shown interacting with others the camera angles reflect his height (or lack of it), and putting in a full sized character would mean that at the angles used we would be looking at their knees or feet.....or, in the case of the reverse angle being used, all the way up the length of their body to their face, way up at the top of the frame. The only instance where what you talk about is achievable is the scene where Yoda is talking to Obi and Mace(?) and is sitting on the hover chair.....in that one scene he is at aproximately the same height as everyone else. Everywhere else you have the problem of high or low camera angles, bad eyelines (assuming you wanted to use a full height character instead of Yoda), backgrounds being off due to the camera angles......it just doesn't work.....not simply by overlapping him with a bigger/taller character.