I think its very likely that there will be a 4th edition at some point. The 2 alternatives are the game ends (definetly worse) or the current edition keeps getting larger and larger. the nature of the game is a complex game, and as you increase options you will increase the learnign burden on anyone that wants to play. I think one of the key things they tried in 3rd edition was to reduce hiring options, and so reduce your complexity in crew creation compared to 2nd edition.
I don't have an answer. I can say that people are probably going to be very against the MTG model, since that is worse than the current complaint that "new releases are better than old models" since it would actually invalidate them, rather than just make them a bad choice.
Before I started playing Malifaux I had no understanding on the production of figures, distributuion and even shelf space/SKU issues. I have done playtesting over the years, and I can say that none of them have had the intent to produce more powerful models than before, even if the outcome of them was that.
Wyrd have produced several simpler and more contained games. None of them have been as popular.
On the important question - Collodi,.
Whilst I like the concept of the character, every rules iteration of it has been one of my least favorite figures to face or use. So if I never have to see a collodi again, I can't say I'd be upset. Of course I'm sure that there is a possible version of Collodi out there that I would like, but his style overlaps with too many other neverborn at the moment so I don't see a huge reason to bring him back. (I think out of the first edition henchmen I own 2 Lucius, 4 Kaeris, 2 Mollly 1 Vonschill and 1 Ophelia and no Collodi. At the end of 2nd edition I had every master but 4, one of which was collodi. His loss does not trouble me. Out of the 10 dead mans hand models he is 10th on the list of ones I'd want returned, certainly behind the electrical creation, and even behind the marionettes. )