There is enough Proliferate in this deck for all of Magic history. I love it. Here are the planeswalkers (Nissa is shown in the Grixis post):
Jian Yanggu is really important to place counters on creatures with no counters.
Vivien's -2 ability allows me to cast an extra card, even if I have to pay the cost, and I can cast it anytime.
I am untapping lands with Kiora. I am sure it can be used to untap mana rocks.
Ajani's ability to put a counter on each creature is really strong.
Nissa is much better suited for a mono-green deck, especially for it's ultimate ability. Turning lands into creatures is really powerful, and in a deck full of proliferate, those lands can become even stronger creatures later in a game.
Here is the deck.
I made a copy of Ajani with Spark Doubler and added counters twice: sweet!
So many cards in this deck proliferate, that the blue ones are outnumbered by the green ones.
Here, I get to use Vivien's Arkbow.
The better creatures for a Proliferate deck don't need any help in getting counters.
Vivien lets me pick Nissa here.
Another Proliferate example.
Nissa turning lands into creatures.
And then I can buff the land-now-a-creature.
Nissa's ultimate would be absurd in a deck full of Forests.
Many lands-now-creatures.
Thuder Drake gets a counter from the second spell I cast.
Panhelion II is just too heavy, IMHO.
Proliferate triggered by Evolution Sage.
Hydras can get really big!
...really, really big.