I think 2 distinct builds are a good thing for new abathur players, each one for another situation suited.

The one thing I would add, is that on small maps you can take Prolific Dispersal instead of Ballistospores for the pusher build (incase the Assasin's hat doesn't fit), the smallest map being Haunted Mines, unless you wanna backdoor - which isn't as strong any more after a nerf (Abathur neeeerfs cause of pros..).