Now I know that the successor projects are probably prioritizing things like fighting, the mission structure and so-on, but seeing as how it is never too early to contemplate the future, I'd like to share my thoughts on base building. The things I liked most of all about the CoH base editor are the following:
1) The free textures for the walls (all five heights), floors (all three heights) and ceilings (all three heights).
2) The variability of the rooms. I liked how we could determine the height of the floors, the height of the ceilings, and the configuration of the rooms through the floor and ceiling editor.
3) The grid system. I know some may disagree here, but I liked the ease and flexibility the grid gave you, over a more relaxed placement method, such as SWG's system. SWG's editor was a kind of geo-relational system based on units derived from the position of the placing player. While this was more realistic, it was an absolute nightmare to make everything sit and orient correctly. In CoH's system, every room had a three dimensional grid, and every object took up a given amount of space on the grid. This made planning and placement easy, without sacrificing flexibility.
4) "Solid" objects. We didn't fall through objects, so we could use objects to create staircases, sub-floors, walls and so on. SWG's system made it possible to walk through objects. As a result, we couldn't create any structural elements.
5) "Lego-like" construction elements. We had desks and bookcases that we used like Lego bricks, and we used stacks of them to create the aforementioned walls, floors, etc. They came in a variety of textures, so we could create wood walls, concrete walls and so on. We also had curved pieces (thank you curved cabinet!), flat pieces (thank you floor tile!), columns, big structural elements (thank you sewer set!) and "one-way glass" (thank you whiteboard!). We also had "special Lego pieces" like florescent lights (on and off), street lamps (on and off), ramps and other pieces that allowed us to create cages, railings, industrial staircases and so on. Tis shows the flexibility of the system; items created to serve one function could be made to serve many functions.
6) "Nesting" objects. In the editor, we could overlap one object into another, to fill up any space. This allowed us to create seamless structures and complex environments (like the vaulted gothic structures you might have seen with nested large arcane floor spires).
So, more or less, I think CoH's system had it right. But here's the places where the Z projects could improve from CoH:
1) Complete texture map skins. Most of the items available in the base editor had only partial texture maps (like many of the sewer pieces, arcane pieces and tech pieces). As a result, things like the desks and cabinets had to do most of the work for things like floors and walls, since they were fully mapped on the top, bottoms and sides. I always said that if Cryptic or Paragon could have only added bottom, top and side textures to the existing items, it would be the greatest boon to the base builders since I-6.
2) The "workaround" reliance on tools to stack. We learned how to use floor safes, floor tile, cubicles and large lamps to "hoist" objects into their position on the grid, but we could have used a better system of placing objects that allowed us to move in three dimensions.
3) I would have preferred a more "notchy" way to set angles. We could "spin" objects, but it was difficult to replicate...say...a 45 degree wall, without the use of careful measuring and "jigs." Perhaps if you allowed objects to be rotated at 5 degree intervals, it would make spinning objects easier.
Those are just my thoughts as a veteran CoH base designer. I liked CoH's base building system a lot. The basics are good, but there are also ways to improve it.