DHL probably works, it's the old mail monopoly, still by far the biggest parcel service. I've never heard they make that kind of problems.
However, another matter is that many people in Germany make orders up to 22 Euros, because those are import tax free. Above that, if the order gets inspected, you pay an additional 19%. Which means in turn that you don't want to pay for very expensive shipping, because, well, shipping shouldn't be more expensive that the products you order
A DHL option would be nice, for sure, but many would stop ordering if plain, cheap China Airmail were not available any more. In fact, before Heath Cabin did start offering Airmail, very few people I heard of ordered from there because it was just far too expensive to have it shipped. (And it's still lagging behind "the competition" because many old hands are used to order from elsewhere and of course recommend to others ordering from there - via Airmail.) Those that did order with EMS were either prepared to pay the 19% or they hoped there would be no custom inspections. It's not a risk many take. I know I don't. And I'd really mind if I couldn't get at my DripTips and flavours any more :O