Okay, seriously though... let's kind of knock off the sniping? We're all just folks here.
First off, 'fun' is inherently a subjective term. What is fun for one person is not fun for another person. For example, when I was younger, I really enjoyed FPS's. Played the original DOOM, Quake, Unreal Tournament... then it kinda lost appeal for me. These days, I really can't stand them. Did the games get worse? No, of course not. But my enjoyment of them did.
There's different strokes for different folks. Some people like big kitchen sink modpacks where balance is strictly a secondary (or tertiary) consideration, and there's many 'unintended synergies' to exploit. And for those people, most FTB packs are right up their alley. They've at least been somewhat curated so you don't have a dozen different types of copper generating in the world, and generally lets you get on with playing the game.
I will agree that FTB's strength is also its weakness... the demand for more tightly curated packs is higher than it was when FTB first started its gig, and the FTB team hasn't really kept up with that very well. Of course, it also takes FAR more effort to produce a more tightly curated pack, and as the number of mods in a pack grows, the difficulty to maintain cross compatibility while reducing the number of 'unintended synergies' grows *geometrically*. So either you keep a slim 'lite' pack, or you dump hundreds of man-hours into the pack for proper curation. Neither are attractive propositions, especially since the depth of the mod list has become something of a... ahem... 'appendage waving' competition.
So yes, FTB packs are... shall we say 'conservative' in their output. But that's not necessarily a bad thing overall, it is just *a* thing. And at this point, it's kind of their brand recognition at this point. You want a pack you know won't crash you out but isn't going to be using any bleeding edge content? FTB packs are going to be your go-to, and people know it.