Let's talk for a second about Pioneer in the context of Magic: The Gathering formats that have come before it. In this article, I'm inclined to discuss what older formats have had banned from them from the get-go, and how this early in the life of Pioneer, the relative lack of bans is preposterous.
So, as can be seen from the above list, all cards from Return to Ravnica on towards present day's current set Throne of Eldraine were legal from the creation of Pioneer, save for the fetchlands. These cards were always known to be powerful deck-thinning forces of eventual mana ramp, as well as amazing sources of landfall triggers, for where that mattered. I daresay that if they were legal today and Hedron Crab was in the revisiting of the Zendikar setting (Battle for Zendikar), we would have a mono-blue Mill deck in the meta, and even that would pale in comparison to decks that better utilize the fetches to their fullest extent.
At whatever rate, other formats have had far more extensive lists of banned cards from their inception. Twenty cards were banned from the original set of cards as of the creation of the very first DCI ban list for Magic, not counting the "ante" cards. 21 cards were initially banned from Modern when that first came into being. And now Wizards has created a format that, almost a month into its run with weekly ban list updates, has less cards banned total than either of those formats began with. For the sake of information, there are exactly nine total cards banned from Pioneer. Let me rephrase that: Pioneer has, three weeks in, less than half the cards banned from it that either Modern or the original ban list had.
I do not think this is because of a better quality of card creation. Far from it, as the most recent Standard bannings show. I think this may be a further grasp at customer/consumer retention, which I can't exactly fault Wizards of the Coast for, but I'm of the opinion that they can do this in a better fashion with the tools they already had.
What do you think? Should Wizards of the Coast ban more cards in Pioneer? What cards, if so? Are any of the cards there for undue reasons? Let us know!