It boils down to this:
- Are you travelling with family/kids?
- Do you have a flexible budget (able to consider more than the cheapest options)?
- Are you easily annoyed or frustrated while travelling?
- Do you have onward travel once you have arrived in India (by road, train, connecting flights, etc.)?
If the answer to any of the above is YES, I wouldn't choose a late night flight.
... these flights are prone to unruly passengers, dirty aircraft, and so on. He even mentioned that these flights are called punishment flights by the crew, because no one wants to be on this flight.
There is some truth to this. Keep in mind that there are a fair number of Indian labourers in Dubai. This group of people is always looking for the cheapest flights between Dubai and their destination in India.
Consider the following factors:
It all depends on what it is that you can afford. If you can afford to fly business class, you will receive good service on almost all airlines. Bear in mind that airlines like Air India will probably have more rowdy passengers in general and you probably don't want to spend business class fare on such an airline. However, Emirates or Jet Airways will give you good service regardless of the flight times.
It is relatively easy to find a variety of airline options if you are going to a major city like Mumbai, Bangalore or Delhi. However, if you are going to a second tier city like Goa or Pune, your options are limited to Air India and possibly a couple other airlines.
- Alternate starting points
Sharjah airport is the closest international airport to Dubai and the airline that flies out of here is Air Arabia (budget airline, popular choice among the labour class). However, you also have Abu Dhabi which has options like Etihad Airways. This one, like Qatar Airways offers good service- it is something to consider if you have a couple hours to spare and want to visit Abu Dhabi.
So my question is: How bad is the situation really and is it worth to avoid these flights and fly other routes, even if these other flights might be a little bit longer or more expensive?
If you are a single traveller, it is easier for you to adapt to noisier and rowdier flights. If you are with family and kids, you probably want to have a more relaxed journey. All in all, I would say that you are better off choosing an airline like Jet Airways or Emirates at a non late night time.
If you don't, it is still just a 3 hour flight. However, if you are not familiar with India and are going there as a tourist, you want to save some energy for what might hit you when you get to India :)
If you are not a tourist and are familiar with India, then you are probably used to rowdy people and should have no extra problems.
Edit: a matter of perspective
After reading the other answer, I feel it important to mention that what some people may think of as unruly and hectic, others may not. It is a matter of perspective. Since the OP mentions that they are originating in Europe, I think it is safe to assume that from a non-Indian tourist's perspective, passengers on some of these flights tend to come across as relatively abrasive.
I can say this out of personal experience- I am a non resident Indian who has lived in Dubai and now in Canada and travels to India once in a while. I find myself losing patience when travelling in India especially after having lived in Canada.