We've been asked to comment, so will do gladly.
Firstly, the problems that Soundwave has had with his Haibike aren't because its a Haibike, or because its an eBike, its because he's using wheels that even in the non ebike world have a shocking reputation.
No-one in normal mountain biking uses those wheels for lots and lots of good reasons. Most people who ride eBikes however don't use their bike nearly as aggressively as even an average mountain biker which appears to be why most eBike customers seem to be ok with those wheels.
Regarding if an ebike would be capable for the type of trails you're talking about... the answer is look at the brand your buying. If they make normal bikes that could take the abuse then the eBike will be able to. If the eBike is cheaper than a normal bike that you wouldn't expect to be up to it... then it won't last.
Bosch, Shimano, Yamaha and Panasonic drives are all designed for proper offroad use, they are used by people all over Europe who ride in proper mountains and use the bikes instead of the ski lifts. They can cope.
I have raced semi professional downhill on the world cup circuit and when I ride our eBikes... i generally ride them like I've stolen them because I've not paid for them so I can give them a real thrashing around the Peak District here. They can take it.
The extra weight is an issue but you learn to cope with it. Its nowhere near as difficult as getting used to riding a motorbike. I've done a bit of Enduro MX and at speed I was at ease on the bike because it just felt like a DH bike with an engine. However at slow speed my balance was all over the place because I wasn't used to the weight. As with everything you get used to it.
The extra weight is tiny in the scheme of things.
If you buy a bike with quality components from brands that are trusted and respecting in normal MTB, they won't have a problem on an eBike.