I understand your concerns, Mike, about how complicated NSIS may be in a year or so, but I'm also sure that many of the people on this forum are going to come up with a neat little GUI or wizard that will contain all of the basic features you like now, but still be able to run on top of the very latest NSIS engine. And even if you still write the script directly, I doubt that many of the current commands and functions are going to change so that you would have to re-learn how to do them.
In other words, your current scripts that you are writing now should always be able to compile under that latest NSIS compiler (barring a few changes that are supposedly for our own good...
I also understand that you may want the very smallest NSIS engine, and that you don't have a C++ compiler, but I'm sure many people on this forum, including myself, would be willing to compile a version with just the features you want and make it available to you somehow.
I, for one, enjoy the opportunity to look at the source code of a well written program and the opportunity to hone my programming skills by *trying* to add features myself.