Organizers would no longer gain much revenue from selling table space to vendors, and the WotC budget for these events would probably result in fewer tournaments for lower prizes
Doug Beyer was a creative director at the time and Jessica Lanzillo, the other creative director at the time, went, OK, OK, you know what
I certainly don't want to squelch the other side's voice
Mark Rosewater has said on his blog that future battles might not be Sieges and might not be double-faced cards, but for now theres only one style of battle card to worry about
When a deck is designed to amass an army of devastating Demons, assembling a group of four Demons at once is a rather easy feat to achieve, especially when you have access to mana cost reducers like Heartless Summoning and Herald of Slaanesh.