I think no-one at Formula1 single handedly in the last couple of years have been able to match Newey.Both the cars have been runaway successes(RBR 7 &

. Seb alone winning 7-8 GP's till now this year proves it. Last year should have been equally dominating had not it been for reliability issues & rookie like mistakes.
I do think at this point of time taking on Newey as the group is the best option. Mclaren got Sam Michael to support Paddy Lowe & to be honest whatever his trackside job is in name,he will be putting technical feedback because that is his strong point. Ferrari are roumoued to be using Rory is a big way to support Pat Fry & Luca has openly said Ferrai will take on Red Bull as a technical team & not a 1 man show.
You see Mercedes-Ferrari-Mclaren adopting somewhat similar strategies. I think the 1 man experiment has flopped for the last 2 years.In case of Mercedes it was essential to significantly beef up their staff,top & bottom because they dont have enough quality as the top 3 & I am not sure if Bob Bell alone can beat Newey,who has fantastic staff sorrounding him.
I think it is a smart move & we can hope to see Mercedes challenging the Top 3 a lot more. I expect a few podiums on merit,the car may not be the quickest from the start but with Costa-Bell-Willis working together I atleast expect decent in-season development. In 2013 I expect race wins & there is no reason not to unless there is big clash of ego's among so many talented people.
Also another point I would like to make is that the recruitment drive is not restricted to the upper layer. Mercedes have been increasing their number of staff significantly with big " JOB ADVERSTIMENETS" seen everyday. Also rumour has it a few worthless people were shown the door too.