Let me explain how I'm gonna approach this:
The proven very top guys get the top cars, of course. The rest of the top seats go to young drivers who deserve the chance to prove themselves as possible future stars as well as some known benchmarks to measure them against. The midfield drives go to less proven (but still promising) young drivers and proven solid journeymen. The bottom grid seats go to drivers who are less promising/proven than the midfield ones, but still deserve a seat. The bottom ones will be reserved for less proven young drivers and some benchmarks to compare them to.
Group one, the top teams:
I would put Hamilton and Alonso in the Ferraris, because it would be entertaining. Vettel would go to Mclaren, as I would like to see him in a different team to see how he would handle it. Then I'd keep Button there as a known benchmark. Kimi would be promoted to Red Bull, and be paired with the Hulk. I'm well aware that the top three might DESERVE the Red Bull seats more, but this would be more interesting.
The final top seats would be Lotus, and here I would give the chance to Perez, who would be paired with a known benchmark like Webber.
I'm a bit on the edge regarding if Mercedes fits in this group or the previous one, but whatever... Rosberg can stay, and let's pair him with... MALDONADO! He has shown some genuine speed, and Merc has more potential than Willams. Than we have Sauber. Let's give Romain one more chance to clean up his driving in a solid car. Pair him with Di Resta to see who comes out on top. The Force India seats can go to Massa (who now deserves to stay in F1) and Kobayashi. The winner here deserves to move up the grid later. Bottas will get his well deserved Williams seat, and would be paired with a solid experienced journeyman. How about Heikki? The final non "new team" seats are the Torro Rosso ones. Charles Pic will get one, and Vitaly Petrov gets the other.
The Caterham seats go to Verge and Ricciardo. Hard to tell if they are any good, and the better seats are already taken, so... Let them battle it out at Caterham. Glock can keep his Marussia seat, and let's pair him with Bianchi, who I have some doubts about, but let's give it a shot. The final seats (assuming HRT still exists next year would go to Valsecchi (he won in GP2 after all). He must be paired with a descent and proven driver for it to make any sense, and here I would go for someone line Sutil.
So, to sum it up:
Red Bull: Kimi and the Hulk
Ferrari: Alonso and Hamilton
Mclaren: Vettel and Button
Lotus: Perez and Webber
Mercedes: Rosberg and Maldonado
Sauber: Di Resta and Grosjean
Force India: Massa and Kobayashi
Williams: Bottas and Heikki
Torro Rosso: Pic and Petrov
Caterham: Vergne and Ricciardo
Marussia: Glock and Bianchi
HRT: Valsecchi and Sutil