This question pops out every now and then. It will still continue to be questioned and debated.
While all views and beliefs are respected, the following comments are just my personal views.
Let first talk about science. There are many topics within to discuss. Let's take for example radio waves. You can listen to songs, communicate and other usage all thanks to the discovery of radio waves. Radio waves existed long before 'time'. It was there all the time. People from all walks of life or different faiths use phone. By the discovery of the usage of wireless communication, is a blessing to mankind. Man will continue to discover more and improve the lives of others. This is a 'tool'. Now, it is again man that decides to take the tool to use for good or for evil.
Again, a chicken or electricity is always there. (Just like feng shui ). To eat/use or not to use is up to individuals. It is always there.
So to debate/ classify or not is also up to individuals. Is there any point, let's ask oneself first.
Whether feng shui will be accepted as a science, will be far from realising until the time comes. Remember, there's always a time for everything? It is up to individuals to expand and correlate the subjects.
Assuming as a tool as well, it is used to benefit the different aspects of mankind (if apply properly). Just like men improving their nutrients through vitamin capsules where they can't obtain from food. No contradictions, isn't it? Nothing to debate about if we don't strain our eyes to try to see the mole in the other's eye, correct?
If feng shui is summarize by the word "energies", then similarly we are looking at the usage of a discovery to benefit mankind.
Feng shui is a common word representing a belief or practise. There are all kinds of people representing such beliefs. There are also different schools of thoughts thus resulting in different views and practises. Religions also developed into different denominations, names, approach, ideology and different interpretations. What we can do is forebearance. Each of our family members, friends or colleagues have their own thoughts and habits that don't conform to ours. If we can tolerate them, understand them (not on bad things), we can also be able to do the same who are just flesh and blood. Insistence on a principle is good for oneself. Insistence of one's beliefs on others are not allowing them to have freedom of thoughts and learning capacity.
If the application of feng shui results in the better lives of people, then it should be appreciated just as well as any other religion that help people to be a better person.
Will fengshui interfere with one's religion? With the right mentality and the proper understanding of what is chinese metaphyics (not religious or mythical feng shui practises), it helps everyone to have a better balance in life.
I shall not go further as the books and webs are full of infomation and own versions of beliefs.
If we open our minds and ponder over this analogy and give reference to the historical changes, we know that all faiths, beliefs, theories and etc can work together for the greater good of mankind.