Medicine ball slams seems to be very good and they're advocated by many - they were mentioned also in another topic about contrast training for climbing - unfortunately I still haven't found a place where I can buy them. I will try on the internet or make one by myself. I am experimenting a bit, and after my initial post, I added two sets of broad jumps to my recruitment, still doing the 2x2x5 barbell lifts before, but avoiding the dumbbell complex. It seemed to pay. Broad jumps seem to have a higher recruitment than dumbbell complexes. That session went very well.
If you or anyone else is interested, I will keep posting updates.
As far as your question goes, I think that it's far more complex than it could appear. My experience is that V7 boulder problems mean a level of power that should be more than enough for high .12 and low .13 routes, so it obviously comes down to the specific issues.
The first thoughts that come to my mind are these:
first of all I would split bouldering and sport climbing, assessing for each discipline what you feel are your specific weaknesses - leaving technical issues out.
So, for bouldering it usually comes down to either fingers strength, locking off, dynamic climbing.
For sport climbing, it usually comes down to either powering out or pumping out.
Core tension is for both and depends on the style of climbing: slab, gently overhanging, very overhanging.
Campusing will only get you so far as it's so specific, but it's an excellent tool, albeit I tend to consider it some sort of secret weapon to be used only as a last refinement, and not as a base training tool, because it's dangerous and so on.
If you like to discuss these thoughts I'll be more than happy to dedicate this topic to those who match resistance training with climbing, I know there are a few on here, to exchange thoughts on this matter. Given that it's OK for the mods to have such a topic, which is not specific to the website.