Create new sites. You will hit a jackpot eventually.
I wouldn't be so certain about that. My 3rd largest site is undoubtedly not only the best site I've ever constructed and in my 40+ years of trade experience and opinion there is only one other site that matches it, yet it seemingly can't get anywhere near the traffic I feel it deserves in comparison.
I want to add more to it but when I have another site that only features 10 widgets yet beats it hands down every day I sometimes wonder whether to move it to a new domain name and host it elsewhere.
We've all seen it, the Google annihilation of sites that simply do not warrant it and the scrapers and scammers promoted above the originals whereas Bing does not seemingly have any of these problems.
So what to do? All my sites do well in Bing etc therefore I obviously do not want to lose those positions therefore my thinking at present is to create a completely new site, new template, new registration details under a different domain name and hosted elsewhere just to see what, if any difference, it makes.
It sure as hell is a crazy thing to have to contemplate however when we have an algo seemingly out of control with ad hoc updates supposedly targetting specific new Google ideas, what choice remains?