Are you targeting this as a single travel lens only? Then judged only on its own merits, this 16-70/f4 would probably do very well what you need it to do. And like Addy says, if you've got the money, then go for it.
But from a system perspective, this lens doesn't make sense to me. Not with that focal length range with that aperture for that price. The f4 maximum aperture doesn't allow for a lot of subject isolation, even at 70mm, and shutter speeds will be limited in low light. For that money, I'd want at least an f2.8, even if it wouldn't be a Zeiss but a straight Sony. It seems more logical to bracket the 16-70 range with an ultra-wide and a tele, and have a fast 35/50 in the middle. The ultra wide part is already covered with the very good 10-18/4. The tele end would benefit from a faster alternative to the 55-210, but as it stands now, the difference in speed between f4 and f4.5 at 70mm is much less than a stop.
