I've been looking at the tank and have been trying to picture if the wood would look better oriented differently. Maybe flipped to form an arch, or one end lower and let it climb towards the surface at a corner, or possibly cut it into 2 pieces and add more. Maybe add some large rocks to one end of the wood and scatter a few random pieces along the length?
I think you are spot on with all of those ideas. The scape as of now is too left, right, center, front, and back.
If you can, position the wood differently in the tank and take a pic of each layout. That would give us all a better idea. I like that piece of wood because it's different and a challenge to scape with. Anyone can take a piece of manzi and make it look good because it's simple.
I would find rocks from large to small so you could have more to work with.
I would also heavily plant with a big tank and hardscape like that. Pond plants work great too. That's where all these plants come from in the first place.