Re: to cross train or not to cross train?
There is simply no way you are going to be a well rounded and capable Martial Artist training in single art. Though many think they are!
The key is finding arts -or certain other training- that compliment each other. And then, unless you are a rare genius... not more than two at a time. You can train in multiple arts and really confuse your body. Then, you can actually wind up worse rather than better.
You need to be able to have time to focus and burn in movement. You can't do that when your body is all over the place every week. You simply will not digest, inculcate and arrive at anywhere meaningful with many arts trained together. To be really bold, I will say to anyone, without ever having touched them "If you train in 4 or 5 arts at the same time....You suck!"
And I have never been proven wrong.