For me, it was the excessive use of slow-motion in the modern series that put me off; think it was Life where pretty much everything was in slow-motion, sometimes super slow-motion, I managed the first episode but no more. I agree with you, there is something preferable about the earlier series. It might be the target audience (his new series are all BBC1, the main, popular audience-driven channel), or just a change in audience preferences, more focus on image and 'wow factor' than informative substance. The same difference can be seen between the BBC channel outputs - a recent documentary by Helen Macdonald (of H is for Hawk fame) about the natural history of the M25 on BBC4, was quiet, reserved, informative and deeply meaningful, it would never have been shown on BBC1