A major drawback of converting to rose joints is that the bearings will only last 10 minutes in normal road use. They just aren't designed for these applications. Good quality ones cost a mint, and race cars use them to allow full adjustment of geometry and to control suspension compliance which occurs naturally with conventional car suspension.
If you want to optimise for road use, fit uprated bushes and have a play around with the adjustments that standard suspension allows. As an example, camber bolts are designed for this purpose and will help towards getting rid of the nasty understeer manufacturers build in.