Anyone who's played Kerbal has experienced that one aplenty ;)
Not sure what the best solution is. For example, maybe they can just improve the control and stabilization software for the system as it is. I'm sure they're really hoping that's possible! It's probably the most likely and cheapest approach.
I'd be really "easy" to land if they had an RCS, just a couple seconds worth to cancel out any lateral movements and rotations - but that'd still be a lot of mass. Maybe if they had an RCS they could narrow / weaken / lighten the landing gear to pay for the added mass?
Or maybe the solution has nothing to do with the rocket. Maybe they need something to grab it on the way down? I mean, planes landing on carriers grab a hook, maybe there's a rocket equivalent for this? One envisions comic-book-ish solutions like landing in a giant net, but there may be practical answers.
Or maybe combine the two. Maybe there's no RCS on the rocket, and no grabbing system on the barge, but rather a supersized reverse RCS system on the barge, big jets that can be fired up and shut off in an instant, aimed at blowing the rocket to induce a leveling force on it.
Or maybe you don't need to apply a leveling force further up on the rocket - maybe you just need to provide some torque where it's touching the pad. Maybe the pad could be mounted on powerful hydraulic pistons to jerk to keep the rocket stable even if it's got some lateral or rotational inertia when it touches down.
I really don't know. But I really hope they get it. And I really hope it's the first option, because things start getting technologically uglier if you have to complicate the landing.