From what I've seen they can be dangerous in the wrong hands due to the high voltage dc currents involved? And the battery fires when they go up are horrendous, they can stay alight internally for days, with massive temperatures involved. The only way to make safe is to drop the whole car in a skip full of water apparently. Even a small Lipo battery fire is a nasty affair.In fairness there's bugger all to go wrong on a fully EV and the bits that go wrong on hybrids tend to be on the ICE part. Steering, suspension and brake components are likely to be similar to ICE cars apart from anything linked to regenerative braking.
However the bits related to the drive systems that can go wrong on EVs and hybrids are bloody expensive.
Another issue with mechanics is that additional precautions have to be taken to carry out some jobs on hybrids and EVs. Main dealers are made aware of these but others may not be.