To varying degrees all representations are illusion, even plain documentary footage is subject to both selective filming (a form of author editing) and subjective reading, interpretation (a form of consumer editing).

In cinema all performances are obviously illusion, all actors are people pretending, even natural light is managed, the shot is framed the lines written and/or part improvised.

So it all boils down to the quality of the illusion.

Do individual elements fit together to create a compelling illusion of a reality (even a fantastic reality with laser swords).

In ESB and most of ROTJ Yoda fits as a character in the pre-defined Star Wars universe (like Artoo and Chewie).

In all the other films the illusion isn't as compelling.

Not just because of the choice of technology to create the character but also and more importantly because of what he does and says.

Yoda in the PT isn't just a less successful meld of voice acting and digital puppetry (or in the TPM inferior physical puppetry) he actively contradicts the character as defined in the other films by being overly physically violent and rather stupid and speaks lines like someone doing a crude uninformed parody of the character.

These traits can't just be put down to being the same character earlier in the story. The PT Yoda is an unconvincing joke on every level and an example of everything that doesn't work in the PT.

The author has either forgotten, never knew or doesn't care how the fictional world, he largely created, worked and when using the brand name (which is all Star Wars now is) to make these newer films he failed to reconnect with that world.

Some of the episodes of The Clone Wars animated series (where the visual puppets are more abstract) feel more like Star Wars because some of the people working on those episodes have a better feel for the original universe than was represented in the PT films.