Totally agreed. I won't be rebuying a 3DS until SMT4 comes out, but the activity log makes it hard to play DS games on anything but a 3DS, because I like having my playtime recorded. The activity log is actually my most played software (I've opened it 98 times!). I've been playing a good amount of Mortal Kombat recently and I keep wishing my time was recorded. Gravity Rush's save time problem also makes the idea of an activity log attractive.Vita could really use an activity log app to counteract this sort of oversight. I know it's trivial, but I like keeping track of my hours :\
Maybe it'll come. Right after the alarm clock app.