There is some confusion about extra services (which are mainly non mandatory to the end customer) that are now available on many forms of mainstream travel products such as flights.
Much of the confusion and concern comes from agents who sell these products [e.g. see this Facebook group setup by agents who are upset with the new BA seat reservation charges] [Hat tip: Travel Weekly UK]
Or read what tweeting business travel agent Murray Harrold has to say about the new United Airlines baggage package:

Why should United travelers "save" money of baggage fees? - The fees are not supposed to be there in the first place!!! I mean: First, take something away and charge for it, THEN turn round and say, "Here's how you can save...all this goes to show that airlines have got themselves into a big hole - more precisely, all these bright young exec's...and they are just ruddy clueless how to fix it. What a ruddy shambolic lot. I wouldn't trust any of them to run an airfix model airport.
Murray is worth paying attention to if you are on Twitter as he summarises the agent perspective eloquently.
The problem is these agents are looking at all these ancillary products through the wrong lens. Yes of course it is about the money but it is also about centralising bookings. No wonder agents are upset - but they put the issue down to airline incompetence rather than well considered strategy. The agents are complaining about the wrong point!
To understand what I mean we have to go back to initial principles.
I do a lot of work with small tour operators. Many of them come from a tailor made tour background. They start with the idea that they are based in a destination and can pretty much sell you whatever tour you want.
These tour operators really struggle to be successful online. In effect they are promoting a service not a product.
A lot of my conversations with these small tour operators relates around advice to create a few sample products (tours). These products can then be promoted and used as the basis of a tailor made tour. These products can be listed on a website (and 3rd party websites).
In this situation these tour operators have had to decrease variations of their product in order to be able to market online.
It is the same with working with agents. By decreasing variations it makes the product easy to learn, easy to sell and enables an agent to be confident they are selling an appropriate product.
Back to the airlines. By increasing variations they make it much harder for agents to sell their product. A customer who finds they can't get the information they need from an agent may end up looking on the airline's own website and therefore booking directly.
Summary - if you want agents to work with you, if you want distributed transactions, then reduce product variations. If you want customers to book direct (via centralised transactions) then increase product variations.