There's a lot to be said for constancy. Most of the problems I've encountered with Domino - especially the newer Java based Notes Client, have been due to Java. Lotus Script has it's gotcha's but they are pretty well documented, thanks to those like you Jake who keep such information online.
As Dragon indicates, the rather constant change in Java versions causes a lot of problems. When you adopt a third party frame work, you adopt all of the problems it has today and all of the problems it will have tomorrow. I suspect this is why many long time developers create their own frameworks - as you shared with your Document classes the other day. If it's your job and reputation on the line, you become risk averse and take in hand the tools which are least likely to embarrass you.
So for those of us who can't be choosy, use the tools available and /or required to the best of your ability and worry not about the age of the technology. COBAL, I will note, is still in serious and reliable use - 30 years on.