How to deal with a poor Roll-Player

[Greenish]

On wizard/barbarian multiclass, that can be made well. You'll want just one barbarian level, probably as the first, then martial feats wizard (with maybe some ruathar for BAB/skills) until you can nab two levels of rage mage, full abjurant champion and the rest in, say, knight phantom, eldritch knight or similar.

[Edit]: ^ To above, having the other characters to drag around a noticeable weaker member to share the loot requires some explaining. Not to mention that some, like me, find people who can't (or won't, since asking for help could easily make their characters competent) pull their weight annoying.