Tobirama couldn't master it because after he created it he named it a forbidden jutsu.... He could have if he experimented and perfected the tech.
What's the point of such hypotheticals though? Sure you like Tobirama, he was probably pretty bad ass. But we don't really know enough to say anything about his abilities as a shinobi.
I just get so frustrated when people argue forever about their favourite character, even when there isn't any actual evidence, just because someone may have dented their reputation a little with a slight comment.
Every character has weak points and strong points. We shouldn't be offended by this. People should recognise this and not get so offended if someone says one character could beat them in some circumstance. It gets even worse when people defend characters that no one has seen perform anything in the manga.
And I know this was just a small comment on your part, but I saw your sig and I was reminded of others, sorry...