Is the whole deck soft, or mainly the center panel over the gas tank? CCPs had word-core for the center panel, and it often rots, delaminates, and/or gets soft. Decks are not wood cored and have less problems.
A deck replacement is not a huge job, but the tank tub has to be molded into the decking. The rest is pretty straightforward. I would not use wood for redecking, but would opt for one of the composite core materials.
Hope this helps - good luck!