What is masking?
I'd be curious to know about other ways Parts get placed. Currently, I'm only aware of RWG placing them.
Trading away Parts may be trading away loot. One technique to get loot to spawn in different locations is to use Parts. I know of one CP POI that randomizes entire floors using Parts.
Nitrogen had a very basic masking system, which King and I expanded on with additional layers of extended masking options. In the nitrogen mask, opaque blue is used to block anything at all from spawning, good for maintaining natural water and coasts, so that nitro wouldn't make a giant mess with roads and circle stamps for buildings.
Yellow is neutral (invisible to editor), then, a single green pixel would give you a town, red a city, you set the sizes in editor and generate. No real control, but way better than ad-hoc, and it allowed you to plan areas.
With King Gen, there are 2 masking layers and also a custom water map layer (though this is not as important now that maps will run natively with splat4)
In KG, we used color red to block all spawning. One mask lets you place town/villages/cities, then the 2nd mask allows you chose the zones within those towns and cities, so like downtown/commercial/old or new houses etc.
For your average player, yeah no parts or tiles is not going to be something you want in a generator. But if you know how to use the mask and make the entries for a20, its definitely still a viable way to make custom maps, specially with Compo type sets.
Teragon will likely be the ring to rule them all, though and maps like these are still fun but they come and go unless you spend a lot of time regardless. Im also not sure how much performance is being killed by tiles, this will answer the question for me I hope.