This has been debated a lot. My conclusion from the debates and from my own experience is that the dense woods CAN be voiced a little brighter. But just because they can be doesn't mean the one you happen to pick up has been voiced brighter. If you think about it, it seems reasonable that the tighter grain of the dense woods makes it possible to get a smoother, purer air stream from the windway. But that doesn't mean that the particular recorder in your hand was actually voiced to do that. Plastic recorders tend to sound plastic and a little cold because of the super smooth internal surfaces. The internal texture of wood make the air stream from the windway not quite as pure, and thus a little warmer sounding. I think the internal texture of a wood recorder softens the way the sound reflects off the internal walls and contributes to the warmer sound.
So my opinion (meaning that I do not present this as indisputable fact) is that the tighter the grain of the dense wood, and the more polished it is internally, the brighter and "harder" it CAN sound ... if it was voiced to be that way.
People have their preferences. Mine is a little more for the softer woods: For example, maple, sycamore, and plum. I rather like the appearance of plum.
Another thing to consider is that the softer woods are much more likely to come pressure treated with paraffin wax. About the only maintenance you need to do is never leave it in a hot car of leave it near a heater because the wax will melt out and make a mess. Otherwise, you just play it and let it dry afterwards. They need no break in period. They are very unlikely to be damaged by sudden changes in ambient temperature (for example, moving from indoors to outside) or changes in moisture of the kind experienced when you decide to give it a long playing session after it has sat unplayed for two weeks. And they cost less!
Some of the dense woods require that you break them in slowly, regularly oil the wood, and avoid subjecting it to sudden changes in temperature or moisture which can cause a crack in the wood.
Keep in mind that wood recorders have a very wide range in how they are voiced -- even within the same model. So you should always work with a seller that will send you more than one to try and who allows you a trial period. You will have to pay for the shipping costs, but that is all part of finding the perfect recorder. When I bought a wood bass, I spent about $150 on shipping to try different samples until I found the right one. If you play in a consort, be sure to try the recorder out with the consort to see if it blends OK.