New airliners have teething problems, then other problems while in service. Interesting to learn that 787 is apparently still not statistically as trouble-prone as A380..
However, apart from some engine and windshield problems, 787 seems to have had a lot which all seem to relate to the electrical system, including batteries, ELT, Toilets, Galley, Brakes, Air Con, and now possibly Wing Flap. With so much of the plane controlled by and reliant on electrics this concerns me more than the sum of all the teething and operational problems.
When comparing these like for like stats, don't forget to allow for the period of the grounding when they would have appeared to be trouble free.