It's definitely a cruiser. The clamshell you speak of is actually used on a class called Power Cruisers such as the VROD and the M109R and the Raider, etc. There are other cruisers out there like the C50T that have a similar seating position to the Valk, along with the Vaquero, the C90, etc.
Cruiser generally defines the style of riding, cruising these bikes tend to have relaxed seating positions, little to no wind protection and provide a more visceral riding experience, generally aren't long haul touring bikes (that's why there is a touring class). If anything the Valkyrie is a power cruiser because it does have a lot of HP and is slated more towards performance than just cruising teh backroads at 45mph.
Bike classifications lean more toward the style of riding than how the bike itself looks. That's why there are touring, cruisers, power cruisers (more HP and more aggressive handling), sport, hypersport, dual sport, adventure, etc. Each bike fits that type of riding style based on it's design.
As for lousy brakes, handling, etc I would also disagree, the M109R and the VROD are both powerful and have great brakes, I've had both. The Raider is pretty good too and if you know how to ride all of them will hustle through the corners, trust me I've kept up with sport riders on mine without to much effort. However the calmshell riding position isn't sport oriented they are more straight line brawlers.
Standards are a whole class that was around before most of any of the current classifications existed, these were your CB1000's, Suzuki GS models and now a whole new crop of bikes out there like the VMAX and new Kawi, suzuki standards that have RR motors detuned for streetability and have a much more upright riding position, this also bleeds into the Naked category, tehnically the Valk is naked too, but isn't in the naked category, it's more of a cruiser.
Of all the classes out there "cruiser" is definitely the most applicable fit for this bike.
