Your feedback is much appreciated. I, myself, do not use many things that are included in the distro. But we have to cater for as large a user base as possible... both newbies and veterans alike. The reason I included all those packages by default is if a newbie uses this edition, as much as possible should work out of the box for him. And if not, then at least the tools should be available to get everything working. It is better I think to have things work out of the box which you can then turn off if you don't need them... rather than having to search for and follow guides to get things to work. The number one reason people use Mint is because it 'just works' with minimal work.
On the other hand, we have also included tools to turn off the things you don't need. Of course~/.fluxbox/startup is the easiest thing to edit... but there is also sysv-rc-conf installed by default. This gives you ultimate control over the services that run on your machine. And it is easy to use. We try to reach an ideal compromise and I hope we are close to that for most users.
About desktop effects: The primary reason I included this is because I believe looking good is a feature. A polished interface enhances user experience and I think just because one uses a lightweight desktop doesn't mean it has to look like a system from the 90s. The desktop effects are handled by xcompmgr which is a very lightweight compositing manager. Even then, a system check is run and it is started only if the hardware can handle it. And it works very well on my own machine which can't handle any kind of 3D game. Also, as you mentioned, I have made disabling them as easy as possible. Again, I hope this is a good compromise.
About including GUI options: Modifying the installer is an undertaking that is larger than I can handle. There are many things we as Mint would like to change in the installer and hopefully starting with Gloria we will be getting closer to this, at least from a developers point of view. Also I would like to include a custom GUI tool to configure aspects of this edition that require editing config files at the moment... which is why I asked for some help from anyone with some Python skills... No one has come up yet
Please do contribute to the discussion for the Gloria release viewtopic.php?f=142&t=24183
I can't promise that your requests will be fulfilled... but I will listen and consider them seriously