It's just too expensive to ever be efficient, even with two modes
It seems like it just might be fast enough (of course those plays outlined above were of the optimal sort) that it may not need any Kraken Hatchlings, Isleback Spawns, counterspells or the like to help it get there, though you may never end up playing Jace's Ultimate because he'll probably take a lot of beats, but hey, that's almost the same as gaining life, and anyhow, once he's dead, you could very well have drawn into another one, so that works out too
Perhaps more importantly for a shifting metagame: Not only can Toll of the Invasion rip a Planeswalker out of the opponent's hand, it can make a body to attack one later
You even get two angel tokens to further buff your army, though angels wont gain indestructible this way