Stupid and naive are not the same thing, Naive is not knowing the difference. Your own words reveal the answer.
obviously I don't know you or this situation, but seems a bit naive all the way around. Naive from the company stand point and possibly naive from seeking our input where if you are a true professional having this figured out already. Not being snarky here, kind of like the surgeon saying "where is that tool with the sharp edge" Since you have asked my advice, here it is https://www.youtube.com/watch?v=1-mOKMq19zU
The camcorder is fine, but really more a test of your skill, so how good are you? If you are good, then the camera is good. The question that begs to be asked and only YOU can answer it. Any camera or camcorder is only as good as the person using it?
I would definitely keep the camera you have and get a gimbaled stabilizer, get the free magic lantern software and shoot raw assuming your laptop will handle it. Making a move to the Gh4 etc doesn't sound like an upgrade to me, but simply another camera choice, you have a fine camera with the rebel and learning to use it effectively and creatively, those techniques will work with any future camera store bought or rented. In addition any money left over invest in training which will make a bigger difference that replacing your camera as does adding sound recording.
I am not trying to diminish Michael words, but take a different view. Beautiful imagery is more a vision of the filmmaker and craft and less about the camera used. I think the exercise of using the camera you have teaches you the skills needed to make beautiful images, what ever is perceived to be a fault with the camera are overcome with skill and perserverence and if your experience is switching equipment when facing challenges that is what you do and if your experience is to adapt, be creative and skill to meet challenges, that is what you do.
Just a different point of view that the prior comment.
I second the motion for the Tascam which makes alot of digital recorder models at various price levels. Often compared to zoom, but dollar for dollar when the same priced tascam is compared to Zoom, the Tascam will have a more robust enclosure and will have more controls in hardware as opposed to everything in software. Sound quality will be similar, but Tascam has a practice of giving the customer more for their money when compared to the competition (Note All mfg make a variety of models at a variety of price points, so compare models at the same price)