I'm not talking about gameplay visual novels as a whole, I'm talking about this specific one. Of course, this is only my opinion and obviously I don't have anything to do with the reading club aside from that I've been watching the topics.
The problem I would expect with Daibanchou specifically is that the game has a lot of different characters that have their own little substories that it uses to fill the time between things happening in the main story. There's nothing wrong with this, but since the player's actions determine which characters you get to know(and even which characters you get, period), even two people playing the same route could have very different experiences. Also, Daibanchou is a conquest game and it's possible to fight your opponents in different orders, which will also change the way a player will see the story. I just feel like it would be hard to have a good discussion about the story of the game with first time players when the game experience can vary wildly from game to game.
Compare it to your own example, Eien no Aselia. In that game, aside from route specific and new game plus events, the game is going to play out more or less the same every time. You get the same characters for the same chapters and the events are scripted to occur at the same times. It's easy to discuss what's going on in that game because everyone on the same route is seeing the same story(possibly minus some side events if you let someone die), even though the game part might play out differently for them. It's a much better choice for a reading club setting.
None of this is to say that Daibanchou is a bad game. It's not going to be for everyone, but I would certainly suggest people at least give it a shot if they're okay with Alicesoft games. The variety that makes it hard to discuss based on one playthrough is a huge upside in my opinion, just not in this particular setting. Though, again, it's just my two cents and it's way behind anyway so it probably doesn't even matter.