You should absolutely care about power draw on a gaming GPU, because how much power the top-end card draws has certain limits that you can't exceed. 2x 8-pin PCI-e power connectors can supply a total of 150 x 2 = 300W + 75W supplied by the PCI-e slot itself = 375W total. So your nominal power draw cannot ever exceed 375W unless you are insane and want to use 3x PCI-3 power connectors on your video card. I don't think AMD are insane, so I'm not expecting Vega to sport 3x PCI-e power connectors. We can assume Vega will also use 2x PCI-e power connectors.
The 1080 Ti actually has a power limit of exactly, you guessed it, 375W when set to the highest power limit allowed by Nvidia. So Nvidia requires 375W to supply a 1080 Ti going full-tilt with max core voltage and power limit. Now we look at our friend the RX 580.
http://www.tomshardware.com/reviews/amd-radeon-rx-580-review,5020-6.html
The RX 580, a card which competes with the GTX 1060, draws almost as much power as the 1080 when it at max overclock. So it is more or less offering half the performance of the 1080 while pulling about as much juice.
Now we know that Vega is going to be TSMC instead of GloFo, but unless Vega is some incredible miracle of efficiency compared to Polaris, there is absolutely no way that it can come anywhere close to offering 1080 Ti's performance while also staying under 375W power usage. If Vega offers roughly 1080 performance while pulling 1080 Ti power it will be a massive improvement over Polaris.
So yeah, we're not pretending power draw matters on a gaming GPU. Because it's actually the most important thing right now. The amount of juice these things require to blast those 4K graphics straight into our eyeballs is already hitting the limits of what you can reasonably expect a computer to be able to supply.