One of the problems I'm forseeing is the fact that many of these potential switchins could very well be holding a CB.
Coming in on a CBTar's (or CB Rhyperior's) SE makes that a guaranteed OHKO even with these EVs, which is no good at all. Coming in on a either of their EQ still doesn't tell you that you're up against a CB variant because you can't see the damage so can't tell if it's CB, DD or anything else. If it happens to be CB, your Featherdance is likely to be wasted as it is switching anyway.
Similarly coming in a Weavile with any kind of boosting item is still no good (regardless of whether it be CB, LO or Expert Belt) as Ice Punch is now a 2HKO and he is faster. Infernape is a similarly extremely high risk possibility as if it NPs you're completely stuffed.
The thing is, when it works it's not particularly bad. The problem as far as I'm concerned is that when it doesn't work, it tends to fail more catastrophically than more traditional options.
If your opp is CBTar then when you predict right, you're just another CBTar counter who was successfully predicted EQ. Your payoff is good but no better than anyone else's. If you come in on SE though then you have just lost a poke, whereas many other CBTar counters are more forgiving of mispredictions. And in a long battle against a decent opponent, you will have to make so many predictions that many of them are bound to be wrong.
That's one example but it doesn't get much better whether you come in on Boah (shudder), CBRhyperior's SE, Rhyperior as it Subs, SD Outrage Chomp as it SDs, SD Weavile as it SDs, SD Infernape as it SDs, Mixape as it NPs, MoPcross as it Subs..
I guess it's good if you like living life on the edge and allowing yourself no room for misprediction. But there are so many other options that give you just as much benefit when you get it right, with much lower risk for getting it wrong..