The original Tizen was designed as open source platform. However, after Samsung bough it, they have changed it to be a stripped down version of the androids that we see in our phones. I would assume they have made it more locked down than our typical android platforms. They did this similar to what Apple did when designing theri ios, so the dev's has to conform to their policies and make it harder to crack. Its all about money.
So even though the 2 watches are almost identical in terms of hardware, the first thing to do is try to unlock the firmware first, then we can see if it can be modified to fit the gear 1 or even any other smart watch.