Well that doesn't mean that the talent is good. It only means that you are a good player. Besides I doubt that you only played Malfurion from rank 45 till you got to 1. Am I right? To say it short you can even be a better player if you would pick another talent. Or do you really want to argue that the 59 HP more instant heal on level 20 does make a difference? To compare: an Abathur deals 58 dmg with one hit on level 20.

Hotslogs is just a number. I got to rank 1 with this build.

Please take a look at my guide. I did some calculation on rampant growth. I would suggest to take another talent. If you look at Hotslogs you would even see that it has the worst win ratio on that tier.