I wouldn’t expect MP assets to exist as final content per se. if I buy an environment asset I’d expect to be able to use the props as they are and make use of modular pieces to make my own buildings and of course to assemble my own scene (with multiple roads etc). probably tweak the material or redo it entirely (but only cause I’m a tech artist and I’ll want this and that for my own material anyway). maybe make slight texture variations of the props and arch modules.
but I wouldn’t expect to have to rebake the textures into a different UV layout because whatever reasons, or reduce/increase the polycount, or change the model topology to make it more suited for a topdown view, or completely re-modularize an asset that wasn’t modular (i.e. the bumping pub’s architectural meshes, which is an otherwise awesome piece), etc.
as a customer, for me the purpose of the marketplace is to save time by spending money. if in the end I have to also spend a large amount of time then it’s not good. and of course if I spend the money and can’t use the asset it’s even worse.
for me a character is way too much project-specific in terms of all the connotations a character brings, which is why it’s understood that marketplace characters usually need to be generic and would hardly ever be used as a game’s main character.
to me a landscape is also not good. a landscape needs to be modified to suit the gameplay. and the more you do it the more out of place the additional textures will be (talking about flowmaps and such). even the regular painted layers will differ in quality (hand-painted areas vs. untouched areas with the nice distribution of layers as they come from WorldMachine)
not taking it personally. in my personal project I’m still making my own assets by hand but at the workplace I’ve worked with outsourcers so I know what to expect. personally browsing through marketplace assets and integrating to fit is a skill I’ll have to acquire for a future personal project though.