The economy of Japan should be more closely tied to China's in order to prevent conflict in the future. Today, Japan and China have several territorial disputes that threaten to erupt into armed conflict. If the two contries have closer economic ties, they will be less likey to go to war with each other.
No I do not think that Japan's economy should be more closely tied with China's economy. Japan is it's own country. It is not the same as China. Japan's economy should stay true to itself. If they want to share similarities with China's economy, then they should feel free to do so.
China and Japan are two different countries with very different key industries. China's key industry is manufacturing. Japan, on the other hand, specializes in hi-tech gadgets and automobiles. Additionally, China is known for inexpensive low quality items and Japan is known for the quality of the products it produces. It would not be beneficial for Japan to tie its industry to China's. To do so may trigger a big lash toward Japan similar to that which took place in the mid 80s.
There's no sensible or reasonable way for the Japanese and Chinese economies to be tied together. Japan is far different from China when it comes to manufacturing. For one thing, Japan isn't the nation everyone else outsources production to -- they developed their own products, made them, and successfully exported them. China lacks imagination required for the creative spark in an economy -- they just make what other people pay them to make.
The economy of Japan should not be more closely tied to China's. They are separate and should remain that way. They are making huge strides to improve their economy such as allowing demands for exports to grow. I think they will soon have a strong economy if they keep making smart decisions.