Regional trains are as clean as any other trains. ICE really aren't that nice (and I find it hard to accept the price difference on that basis - the only reason why I'd ever take ICE is because I don't feel like taking 5 hours to travel from Cologne to Berlin).
They can be crowded around the times people are commuting, but otherwise they're not that crowded and it's easy to find a place to sit. If you're using the 49 Euro ticket to check out places nearby, there's no reason to believe you'll end up in a crowded train. Just make a tiny bit of effort not to take a train at peak times.
They're only particularly noisy if, I don't know, there's a big game locally and people are drinking on the trains. Even in a full train when everybody's going to or coming from work, people are really fucking quiet.
I'm not sure what your angle is, but I'm not sure why you're misrepresenting the state of German regional trains.