Tier 1: We like to charge it, charge it
No way around it: Displacer Beast is flat-out terrible. In theory, the ability serves as a way to escape from enemies; in practice, it completely fails at this because it lacks the threat-dropping capabilities of Feign Death or the temporary damage absorption of Vanish. DoTs will still immediately snap you out of stealth, as will spells in the air (sometimes). Non-players will keep all their threat and keep attacking you. I could maybe sorta kinda see it being used offensively in PvP for feral (open from Prowl, dump some energy, DB out and reopen), but that's pushing things. At this point, I don't think the talent is fixable, and I'm hoping they scrap it and replace it with something that buffs Dash and/or Stampeding Roar.
Luckily, we have two other talents that are much better. Feline Swiftness's passive movement speed increase is boring but very helpful in any situation. Unfortunately, it has one key downside: It does not stack with boot enchants, which makes them an integral part of the decision. Feral will almost certainly be using the Blurred Speed enchant anyway for the agility bonus, so it's really more like a 7% bonus for them. Balance has a little more choice here; they can choose between move speed + 140 mastery or 175 haste, which will likely be a superior DPS option.
Wild Charge, in contrast, has a wealth of situational uses, especially in PvP. The cooldown being so short means you can use it pretty much every time you need it, which is great. Of course, that means you have to use it to gain any benefit from the talent. If you'd rather focus on your rotation, just go with Feline Swiftness. Basically, it's a pretty close call. I probably prefer Wild Charge for feral and Feline Swiftness for balance, but it can go either way.