hmmm... I like this Idea somewhat, but I'd make it +1 to the 'to wound' roll as opposed to +1 strength - which I think is what you were intending but +1 strength makes strength 4 suddenly affect armour 11 and toughness 8, which a re-roll wouldn't help at all with.
-1BS would also have to be capped at 1, or people couldn't shoot fliers or flying monsters at all, but then it means it has no effect on people snapfiring, which re-rolls do.
re-roll morale checks, again you're making it not effective for people who it would have been most effective to. plus we mustn't forget the bosspole re-roll is only conditional, I don't want to kill a boy straight away for +2 leadership only to roll low enough to have not needed it.
I think, as morale tests aren't as frequent as to hit & to wound etc, they could probably still be kept re-rolling. but I understand when people are rolling massed dice which can re-roll to hit, then re-roll to wound, then you have to re-roll successful saves, it does get kinda tedious.
I think you're on the right lines, don't get me wrong; but I have a habit of picking holes in every good proposal. your job is to go fill 'em