Let's not make the same mistakes.
Haiku is all about performance and ease of use/programming, whereas Linux is all about horrendous performance, and making the simplest task an heroic feat. Taking this into account:
-> Don't even think of making GTK/QT/->whatever crap's out there<- a standard part of Haiku. (*)
-> To make a user comfortable with the system (remember, the average user knows nothing about PCs, nor does he/she care. The user doesn't want to "type commands" to do something as simple as "installing a program") it's necessary to have a means of installing/uninstalling programs easily (like in Windows/MAC), something like the "next, next, next, finish" approach. (And it should be somewhat "standard" for Haiku programs installation)
-> Of course, a program MUST be "self contained" only depending on the system functions, and not using 4567776655 3rd party libs that most of the time don't do anything the system cannot do. And if any such libraries must be use for any particular reason, these MUST be provided inside the package.
As GTK/QT/blabla wouldn't be used (as they are not needed) such libraries wouldn't take up much space (1MB should be MORE than sufficient)
An OS will only be successful if it can be seen by commercial developer as a profitable one, and also if the end-user is able to make whatever he/she has/wants to, in an easy and efficient manner. Linux achieves neither, Linux is a perfect example of what path not to follow.
(*) What I'm saying here is not to make them a standard part of the system, they might get ported, but if a program depends on it, it should either provide it in the install package, or download it "on demand" (a feature that may also get implemented in this hypothetic system's default installer software)
Regarding 3rd party libs, the software installer would provide a means (to the programmer) of checking whether a particular lib is already installed on the system, and if so, the programmer can make the installer not install the ones he has provided in order to lessen the amount of "duplicate libraries" throughout the system. But this "duplication" issue is not that important if the programmer uses the bare minimum of 3rd party libraries he needs.
In some other post someone said something about "libs update", which is not that simple if every program has a copy of THE LIBRARIES IT HAS BEEN DESIGNED AND IS KNOWN TO WORK CORRECTLY WITH.
Well this is not an issue really, since the program itself should update whatever it thinks is necessary to get updated, and this, in turn, makes the overall experience MUCH better, because sometimes a lib update may break an otherwise perfectly working program with a previous version of the same lib.
So, let's not make the same mistakes made by the GNU/Linux community...
-> Haiku Is Not Linux <-