Obviously there shouldn't be abusive companies, but those are kind of funny examples to pull out as I would put them all in the mid-sized or larger. TS was the same size as WM (which had artists like B1A4 and OMG), and TS screwed over its artists, ruining their careers, while WM ended up being purchased and merged as a subsidiary under RBW and every member who still wants to be part of B1A4 and OMG is. MBK, on the other hand, simply sucked at managing scandals, but they had tons of artists from T-ara, SG Wannabe, Seeya, Davichi, etc. who were very popular and well-known. So where do you draw the line? Is "incompetent at some very important things but mostly okay" unacceptable?
There's also an aspect of: who is big today may not be big tomorrow. DSP Media used to be part of the Big Three, but after the CEO got very sick and had to step down, they cratered in relevance. There is no guarantee that the companies who would be deemed "big enough" to successfully ensure debuts will remain so in the future.
There should be more matches between decent company & talented idols. Thats what I want.