What do you guys want

I've been building a lot of crafts in a very wide range. Cargolifters, VTOLS, Fighters, Passengers etc... And I noticed that they would always hit below 5, almost like a barrier, or just don't go above 2. So, i'd like to know what would Actually please you guys? Is it caus of low part count? Looks? Performance? I literally don't know anymore.