-- It is believed that Ronda Rousey's value as a wrestler under contract to WWE had a significant impact on the negotiations with Fox. The story also goes that during the negotiations between WWE and Fox executives, it was Rousey's posters that were plastered all over the room clearly showing her immense value.
-- It's possible that if Rousey remained with UFC, this entire deal may not have happened and Fox would have ended up deciding to stick with UFC instead. There's also a quote from a Fox executive when comparing UFC to WWE that suggests that with WWE being a family rated program, it was going to be much easier for them to sell advertising on the show as opposed to UFC, which they had a difficult time selling.
-- One other added element between the WWE/UFC dynamics is that with this new deal, WWE has far more cash in hand in which they can likely match or exceed any offers for talent that would make sense in either WWE or UFC. In other words, if there is another Brock Lesnar out there - who can be a star in either industry - WWE can open their wallet and get that person.
Source: Wrestling Observer Newsletter. Subscription information & prices available at f4wonline.com