I didn't mean that as an insult - I assumed they were rush-jobs. In both cases, the problem isn't the choice of base texture - look at Smoth's models, which are almost entirely bereft of base texture. Relying on a base texture is a recipe for failure.
The problem is that there is no details that are working with the contours of the model. You need pre-shading (put shadows where you'd expect shadows to be) imply some effects at the edges and corners of hard edges. On the flat surfaces, look at real-world metalwork and include some of the seams, panels, features etc. you'd see on such a thing.
A little gradiated highlight along some hard edges, and a glint a some of the corners, can do wonders.
Here, let me show you an example of how some good preshading can make an ugly, low-poly model with flat, un-textured metal look good:
Sorry about the small image, but Sideswipe from Transformers Quake was the first thing that came to mind as the simplest way to illustrate preshading.
Look at the shadow of his helmet on his face, the shadow on his bicep cast by his shoulder, etc. Notice the gradual highlight along every faded edge, the smooth shading of his gun-barrel. Notice how different faces are different brightnesses - the armpit-side of his bicep is darker than the other sides.
Look at the lines on his torso and wrists - lines that do not exist on the mesh. Look at the shading on his torso.
This model is unlit, and it looks good (except for the wonky crashing of his legs into his crotch). It looks better when lit. It's a Quake 2 robot model (made by Phukyumoto), which shows a comparable polycount to RTS models, which is why I picked it.
See the things I'm talking about?
edit: I just realized that model is like 12 years old, when I was playing the Transformers Quake beta. Holy crap I'm an old man.