I was on a double-decker RE to Friedrichshafen, in September, and I didn't find it particularly comfortable (cramped, I would agree) but they're fine for shorter journeys.
Shorter journeys, yes, but they're also increasingly being used for ICs, not only for Regionalbahnen or Regionalexpresse. There's also the issue with the €9/49/whatever next ticket that many more people are now taking long trips by non-IC or ICE trains, so there are definitely more longer journeys being made on them in this way, and not just in last year's cheap holiday frenzy mode.
Re voltage, I think new trains can be configured to operate at different ratings.
Yes, the ICE between Frankfurt and Bruxelles (Midi) does that. It changes voltage somewhere around Aachen. Once recently that facility was broken and because they've taken away all the slower trains between Aachen and Bruxelles it all became quite difficult.
We had the cheap holiday tickets, which was a nice bonus, but I suppose it's also a way for less well-off families to get places (in this case a popular Southern holiday destination).
Yes, overall it's a good thing (although it's been implemented very badly because of the appallingly ignorant incumbent transport minister). It's also going to keep increasing in price. Anything that emphasises slower travel and rebuilding of the decimated network is good.
Shorter journeys, yes, but they're also increasingly being used for ICs, not only for Regionalbahnen or Regionalexpresse. There's also the issue with the €9/49/whatever next ticket that many more people are now taking long trips by non-IC or ICE trains, so there are definitely more longer journeys being made on them in this way, and not just in last year's cheap holiday frenzy mode.
Yes, the ICE between Frankfurt and Bruxelles (Midi) does that. It changes voltage somewhere around Aachen. Once recently that facility was broken and because they've taken away all the slower trains between Aachen and Bruxelles it all became quite difficult.