Maybe I was a bit harsh when stating my opinion of most all-around scripts, but I didn't mean they suck only because I did not write them, in fact they're probably better for me not writing them, but most of them do suck because they all seem to be wanting to impress people with their scripting abilities and tend to cram as much unnecessary functionality into the script as they can. I'm a musician and I would much rather not work with other musicians that do absolutely everything they know how to do on every song, we call that over-playing, and they do it really for no other reason than the fact they they can and they want everyone to know what they can do, so you end up with a song all garbaged up with over-playing instead of a good solid song.
Over scripting can be the same way with themes and colors and things that don't necessarily need to be there but only to make it a bit prettier. Coupled with bloating cosmetics, the scripts also end up with over functionality meaning that by trying to do too many things, the script now doesn't really do any one thing very well, but it does a lot of it. Most users, when they download one of these scripts, will probably only use a small percentage of the functionality of that script. Also they may load the script and look around and decide it's too complicated and bloated and decide to not use it at all. As far as using other people's scripts, I do use a couple of add-ons and I'm pretty happy with their funcionality, stability and performance.
Applications to me are no different, I've argued more times than I care to recall against unnecessary functions and cosmetics being added to mIRC. Emoticons (smilies?), buddy list, more colors, avatars, voice/video support are some of the things I've argued heavily against here in the past and always will, because mIRC is one of the few applications that I like whose author has refrained from over functionality and over bloating and I really appreciate that. I tend to stick to applications that do only one or two things, but do those things very well.
~ Edit ~
My apologies for the long winded reply.