Well if there will be games that absolutely require a second analog the odds are that I won't buy them them anyway. I dislike third-party games in general. And games that use 438 buttons at a time I might as well play higher quality games on a laptop.
But I just realized something... I notice most people dislike the fact that the 3DS didn't have a Second Slide Pad or a second set of Shoulder buttons. Because to them "there's not enough buttons". If the 3DS did have all those buttons I think people would be complaining that it is too crammed with buttons. Just take a look at the Gamecube Controller. Two Analogue Sticks, a D-Pad, Start, A, B, X, Y, L, R and Z buttons. And people disliked it because there was too much buttons.
But if the buttons included with the new Slide Pad (or whatever it's called.) were put on the 3DS by default, there'd be Two Anologue Sticks, a D-Pad, A, B, X, Y, L1, L2, R1, R2, Start, Select, Home, Touch Screen and Gyro Controls. Which obviously is a lot more than the Gamecube's controller. Not to sound offensive or anything to anyone here, but that kinda makes those who wanted less buttons on the GC controller but more buttons on the 3DS a little hypocritical.
I think the reason Nintendo opted to have "add-on" buttons with the expansion slidepad were so they didn't make the same mistake as they did with the GC controller. Not too many buttons, but if they needed more, they'd be able to use the optional additional buttons. No one would complain of too much buttons, and those people who complained of not enough buttons, to suck it up and buy the new slidepad. Because you can't please everyone in this industry.