As far as i readed, Johnston had strong military and political support and his feeling was particullary oriented to the -resupply-. Maybe his criticized style was think out in relation of the perception acquired on the field by the commander at the start of war, the ascertained inferiority of supplies and equipments of the confederate armies. So more than be an effective field commander, i would praise his caution strategy in this sense. Maybe the worst of this sense was exposed at Vicksburg where it seems he had the numbers to 'make that job' (I use -maybe- not because i'm unsure about what i readed but because in history is always better expose own or the universal knowledge with the requisite humility and prudence.)
Anyway, despite Lee has always been glorify, i would hazard his -immoderation- was the cause of disasters like Gettysburg, but like
@Greywolf said, and probably was, the right man for the east.
So wariness can be a good or a bad factor, depending always on the situation and the level of discretion used by who has to lead.
In other terms, maybe funny, like if we're playing a strategy game and we're discussing the two generals accents, i would give INITIATIVE to Lee versus LOGISTIC to Johnston.