On one hand, it is a gimmick, and a lot of implementations of this will be garbage. On the other hand, there are some applications where this not only makes sense, but is actually rather brilliant. Using a tablet for BF4 Commander mode sounds pretty awesome; the top down strategic viewpoint is probably even better suited to the touch interface than it is to a controller. You can certainly touch points on a map much faster and more intuitively than using a stick to move a reticule around and hit a button. Don't have enough experience with previous Commander modes to know whether the resulting higher APM will make any decisive difference in a match (I actually suspect not, but I dunno). It's definitely interesting, especially since you can presumably play with your friends even when away from your console though.
It is interesting, but I hardly think it's the future (for these next gen consoles anyway). BF4 is one of the few examples where I can actually see it being used. You have a pre existing mode, and an interface that actually makes more sense, and is easier to use with that mode, available as an option in a game with a massive fan/userbase. Having all those factors working in it's favour is a pretty a rare situation though.
Most popular console games require controls that aren't compatible with a touchscreen interface, so most of the things devs have come up with so far are add-on gimmicks out of necessity, otherwise they compromise the core product being sold. Maybe if publishers start putting some more traditionally PC based games, like complex strategy games, on consoles it could be useful, but that would
require a tablet to be available as the primary control interface. I think that seems like too much of a sales risk, but maybe if it makes porting games easier it won't be.