Technical director Bob Bell to leave Mercedes in November

[Monty]

I think this is probably bad news for the future of Mercedes F1. Ross brought Bell into the team and this years car owes a lot to the Brawn / Bell relationship. Now Mercedes have a top heavy management team and far fewer 'car' experts.

[Scott]

As long as Lauda is attached to Mercedes, it will always be 'top' heavy. 

Could this be a new sign (as in signature) for Ferrari?

[John S]

I think in reality Bob Bell's work is done at Mercedes, for the last year -maybe more- his role was to specifically to focus on the new regs effort and he has done that remarkably well.

Some suggest that the special engine packaging called for to marry up to an innovative new chassis was his idea, he was also free of day to day work on the then current cars making 2014 his only real goal within the team. The usual tech heads are taking up the slack now and will develop the new car - so job well done by Bob.

I'm sure this parting of the ways is no surprise to either side, and the long delay in his departure time from the team is just to ensure other teams - especially those about to get Honda power - can't easily jump on the expertise applied to the W05.   
 

[lkjohnson1950]

Or, the arrogant Lauda wants to obliterate all trace of Brawn from the team.