I use Sketchup 8 because it is simple and easy to use, but only to make small objects that I can't find anywhere else. I try to prune out as many excess triangles as I can as well and usually I'm only using a single or minimal number of textures. I don't really know what the phrase the OP quotes means; - "The effective system load of this asset is xxxx polygons (xxx from geometry, xxxx from textures)", - I do know though that if the numbers are looking too large that I have to go back and take a look at what I've made again.

And don't tell me to go and learn Blender. I have cognitive issues due to having severe narcolepsy and on bad days using Paint.NET can be more than enough of a challenge for me and I know how to use that.