Next year's regs take away a lot of what is commonly thought to be where Red Bull derives it's biggest advantage (and consequently, Vettel's seeing as his driving style is so in tune with the way these current cars work), and that's exhaust blowing and it's effect all over the car.
The vortices we saw in practice this weekend are a great example. The RB9's was so clean and directed because in this particular regulation set Newey and his team have (with a LOT of R&D money of course, more than any other team including Ferrari) managed to get the car's underfloor to be working as almost virtual ground effect by getting every part of the car to work towards one aim: getting air to the diffuser. It's something they've had worked out since they debuted the major update to the RB5 at Silverstone in 2009 and blew the field away. That car had their version of the double diffuser, but used their already fitted low exhaust outlets to help drive the top elements of both the beam wing and the upper part of the diffuser. It was a compromised double diffuser design, but they made up for it by using hot exhaust gases that no other team was using. Everything since has been based around that concept, something all the other team's seem to have forgotten each year as they look for another panacea (pullrod front suspension, 'octopus' exhaust, passive DRS) to their fundamental design concept issues.
As for next year... the car won't run so much rake (because whilst the downforce advantage has negated it currently, it's not a good mechanical setup), the front wing will have a different flow pattern (will outwash still be the best option or will inwash endplates come back?), and the hot exhaust gases will exit as far back as possible. I can forsee some teams trying to direct this exhaust's flow towards the diffuser, but it will require some major compromises in order to do it, so the benefits would probably be outweighed. The cars will need to be a lot less draggy as well, something Red Bull has made seemingly big strides in this year, but it has still taken them the best part of 3 years to work out, so there is hope for the other teams there.
The biggest factor is how this all will affect Vettel's style. His able right foot has allowed him to get some exhaust blowing advantages in corners, but will be a redundant style as of next year when efficiency of input and no EBD will mean that his throttle modulation will most likely only result in instability and wasted fuel. It's how or if he adapts that will see his form either continue or go through a dodgy patch, in a similar way to how Hamilton has had to grapple with driving in a way mostly alien to his natural style, meaning his sword has been dulled since 2011 IMO. Vettel's invincibility is somewhat circumstancial with these rules and the benefit of having his technical staff so perfectly realise the needs of driver and car, and someone else may be better suited to what comes next. He'll always be a great driver, but whether he ever is the same driver that he has been these last few seasons will remain to be seen.