Conquest of the Horde

This might go nowhere, buuuut...

Is there any evidence of Titanic activity on Draenor?

There's not really any evidence that I know of but it's quite possible that they did have a part in bringing order to Draenor as they have done so to many millions of planets.

It could be assumed since there's no titanic citadels mentioned at all on Draenor that the Titans never went there. -Or-, the world may have simply been good enough when the Titans arrived, so they decided not to meddle with it. /shrug

Or all the Titan stuff exploded.

Because Outland is only like 10% of what's left.

There is an Old God on Draenor, at the least.

As I am not a knowledgable source on Outland in its present state, or past for that matter, I cannot offer any inclusive information though I would suggest looking for evidence aside from architecture. Creatures resembling those not affected by the curse of flesh for example. What is clear is that Sargeras discovered Argus during his travels through the twisting nether which would insinuate that there were some places that had not been manipulated directly by the titans to the extent in which Azeroth was. Regardless of what answer this question prompts, I like the scope of your thought.