I would disagree that unlocks are for people with short attention spans. I bet I've been gaming on PCs longer than anyone here, since 1986 on a Commodore 64 and then a 286. I've seen it all, and I've seen, bought and enjoyed games from Kungfu Master, Epyx Summer Games, Space Quest (countless adventure games, almost everything from Sierra and Lucasarts), Civilization 1, Buck Rogers (D&D Gold Box), Wolfenstein3D, GLQuake, Half Life, Daggerfall, UT99, Giants Citizen Kabuto, Unreal Tournament 2004, Dark Messiah of Might and Magic, to today with League of Legends.
I've witnessed and experienced the rise of gaming just as it was getting interesting in the 80s.
I just don't see how unlocks/achievements are to fix a 'short attention span' in FPS games. I just enjoy seeing achievements popup, in any game. It's a nice addition.
If we had the internet in 1986, and the games had the ability for any advanced features at all (other than the core game), we would have wanted these features then too.
Now does the gameplay suck for Titanfall? I don't know, haven't played it. But I'm certainly not turned off by achievements popping up. I don't work to fulfill them, but find pleasure in randomly making one happen.
I would've taken an achievement in Heroes of Might and Magic 1 back in 1993 or so, when killing a thousand+ stack of human peasants, for example.
Also, I don't really play CS anymore but CS is addictive without achievements, but I find it a nice curiosity to land an achievement in CSGO. No achievement/unlock system is going to keep me playing a bad game, period.
If you want to see what requires a longer attention span, try the frustration of a 1980s adventure game or D&D Gold Box game. Once you're sucked into them, they can be much, much more rewarding than any FPS.
But for me, all FPS games are classified as short-attention span games, there's plenty of instant gratification going on all the time just with the graphics alone.