I think you've made an extremely good observation:
If all christian religions are equally imperfect but by being Christian they are saved then technically all you have to be is a Christian to be saved and it doesn't matter which one, as God will understand?
So i could pick an easy one that only asks that i say sorry every now and then when I do wrong and I can take pleasure in enjoying life knowing loving God is enough hmmm i'll have to think on that.
If the mistakes and shennaigans of the JW's can be excused on the basis of human imperfections why couldn't other religions be accorded a similar level of mercy?
Of course the JW's have their stock answers for this type of question, (e.g. Only we have the Truth, Only we have Jehovah's approval, Only we are preaching the Kingdom, Only we are the faithful and discreet slave, Only we are dicrected by Jehovah, etc.) but every one of these answers are claims that the JW's are much more than just another religion. .
So on the one hand, the JW's are so much better than all other religions that Jehovah is going to kill everyone in those other religions, sparing only the JW's. But on the other hand, when the JW's make mistakes, they fall back on excuses that should apply with equal force to all other religions.
What's wrong with this picture?