While it's definitely possible for adults to have fun, DCL is heavily geared toward families. This inherently makes tables for two harder to come by (especially during the more popular early seating), and the family pools are always crowded on sea days (but the adult pools are typically MUCH quieter). Because the focus at dinnertime is on the rotational restaurants themselves (since they're typically VERY popular with families), this means that: 1) They need all hands on deck in those rotational restaurants, so it makes sense to keep the buffet closed (but still have room service and quick-service options available for those who don't wish to dine in the restaurants); 2) The first seating is a little more rushed since they have to get half the ship fed, cleaned up, and prepped for second seating (with the exception of the first few times we cruised with little ones, we always choose the later dinner for this reason, and I've never felt rushed).
I'm not saying that you're wrong at all for feeling the way you do. But ultimately, you're not DCL's target demographic. We've sailed with Disney nine times, but our kids are older now (18 & 16). We've got one more booked this summer, and I bet that will be the last one as a family until my kids have kids, as other cruise lines just have more to offer for adults. But I don't fault Disney for that. Their product is unparalleled for their target demographic, and it's just not our family anymore (although I will continue sailing with DCL in perpetuity with whoever wants to come with me lol).
I'm not saying that you're wrong at all for feeling the way you do. But ultimately, you're not DCL's target demographic. We've sailed with Disney nine times, but our kids are older now (18 & 16). We've got one more booked this summer, and I bet that will be the last one as a family until my kids have kids, as other cruise lines just have more to offer for adults. But I don't fault Disney for that. Their product is unparalleled for their target demographic, and it's just not our family anymore (although I will continue sailing with DCL in perpetuity with whoever wants to come with me lol).