Renault's struggle to produce a competitive package for F1's sweeping regulation changes in 2014 perhaps hit Lotus hardest as they slipped from fourth in the constructors' standings in 2013 to eighth a year later - above only backmarkers Caterham, Marussia and Sauber.
Four-time champions Red Bull have lost star driver Sebastian Vettel to Ferrari as a result of their Renault woes, but Lotus will hold on to their top man Romain Grosjean for 2015.
And the Frenchman could well be competing at the upper end of the field next term with Mercedes power coming to the Enstone team.
Williams made the switch from Renault to Mercedes power for 2014 and jumped from ninth in 2013's standings to third last year with nine podiums between Valtteri Bottas and Felipe Massa.
And, despite a number of key staff having left Lotus in recent years, technical director Nick Chester believes the move will provide a significant boost.
"I think we can make a massive step," Chester told Autosport.
"We know how much the engine's worth, we know what our aerodynamic problems are; couple fixing the aero problems with what the engine's worth and we can make a big step up.
"Williams have done a great job; if they have good development over the winter it will be hard to catch them, but we'll be trying to get on the back of Williams if we can.
"We lost a few at the end of 2013, but it's still got a lot of strong people who know how to make good cars.
"I think we can bounce back a long way next year."