Using tools with bad handle design is fine for short periods. Do any amount of work with these tools and the body hurts. Do not assume that a maker of tools will put on the ideal handle. From my experience we all seem to have our own personal idea of what makes a good handle. A handle for one person will not always suit another.
I have a large GB adze, and I like it. I would class it as a good all rounder, great for wasting wood from a bowl and great for sculptural work. The problem I have is the handle. For some sculpting work it is too short and that bloody chunky fawns foot on the end, a hand wrecker. They have just stuck an axe handle onto it.
When I use an adze my right hand holds the pommel and this arm or hand is fixed against my body. My left hand swings and guides the adze. The fixing of the right hand is vital if I am to get a smooth cut. Holding this pommel is hard work as it does not fit my hand, so out comes the edge tools to shape it. I sand it smooth, because facets, unless very small, help cause blisters.