Generations isn't that great, but it is to me for one reason. I didn't get into Trek until the 7th season of Next Gen premiered on Sky. As that had finished, the build up to Generations was unbearable. I was 17 years old, at college, and hooked on Trek. Any new Next Gen was going to prove to be great, even if it was contrived and disappointing when watched without the Trek bug I had at the time. It also took me a long while to get into DS9 afterwards, so for a while, this is all I had that was new to Trek to look forward to.
There's still long parts of that movie I love, because it invokes memories for me. Even average to poor movies can great to people because of memories they attach to them. Generations is one of those for me.