Very interesting topic.

I think the real questions to ask are: what causes shelf-warming? Is it possible to not have shelf-warming? I think there are multiple issues.

One issue is - I think in any wave or line there will always be some figures that are more in demand than others which will create the issue of shelf-warmers. Retailers cant/ don't selectively order the "popular" ones- they order by wave. Even online retailers whom are tailored to after market prices order by wave, then sell the figures usually by adjusted individual prices- i.e. BBTS selling warpath for $25, where the rest of the wave is significantly less as they are in less demand.
This obviously leads to the figs that are less in demand shelf-warm as retailers cannot order/stock more until those sell out.

This problem is then exasperated by any fig that is overpriced, in an unwelcome pricepoint/size/ or just not popular/fugly.

One example is the Bruticus you mentioned, the other, ROTF Supreme Devastator. I.e. last week I walked into TRU and there were literally over 30 of them. $150 each. Considering other stores found it extremely difficult to get rid of this monstrosity at a significantly lower price- I seriously wonder how long these will shelfwarm at TRU for.