Personaly stoped using power attacks completly. Too big stamina usage and most importantly, they stop stamina regen. They also deal only 2x more dmg and some rare effects with perks for a price of spending most of stamina and being unable to fight or run for few next seconds. Just power attack benefits doesn't justify their price, atleast surely in higher difficulties where enemies sponge much more hits, in easy modes that's propably viable to one-shot something with power attack insteed of risking getting hit back.
When you get enough perks I think the power attack can be pretty usefull. The problem is, as you mention, the stamina regen stoping. It makes it really really bad to use on low level.
I've made some test and it's clearly a mistake to use power attack in early game (not because of the stamina usage, but because of the stamina regeneration stoping)
I think the problem is that power attack becomes usefull too late in the game, at a point I've adopted another way of playing (yeah like I don't have time anymore for POI's, let's go my way with a good AK47, so I'm not really concerned about power attack anymore)
I think the good way to be to delete the stop of stamina regenation, but add a perk :
- On level 4 and 5 of this perk, you get something very usefull on power attack, but you get the stamina regeneration stoping for 3 seconds like right now.
You could add it to an existing perk like "Stay Down". It wouldn't be abused because it would be exactly the same for an end game player, but it would make the power attack usable for a low level player.
If you think that people need to "regulate" their ways of using power attack, you can't make it worthless, or it will disappear.
Now for those saying that power attack stays good on low level,
On level 1, bagpack empty : Until you get 2-3 zombies, you get enough stamina to kill them all with a club without any stamina problem, using simple attacks, and power attack only when they are down (assuming you don't run everywhere of course, or miss all your shots).
Over 2-3 zombies, if you use simple attack and power attack when they are down you will have stamina problem and start to wait for hitting
Using simple attack, you can get easily the 3 zombies without any stamina problem.
So that's easy, don't use power attack on level. Then, depends how you like to play, if you like looting POI with melee, go for it, but if you're like me and prefer into zombie mass murder with an AK47, then just forget about power attack for ever.