Aside from their multi-genocidal quest, how concerned would the Mechanoids be with improving their physical bodies? Given their mastery of genetics, I'd think they could create even more powerful abilities or, I dare say, sub-species of themselves in order to become more efficient killing machines.
Though, something just came to thought about if a Genesplicer got ahold of a Mechanoid...
True, the Mechanoids have already been altering their own evolution, but they also fall afoul of the same concerns as humans about the deliberate engineering of their own progress....To the Mechanoids, BOTH their organic selves and their machine portions are one and the same, and like current human discussions on the use of genetic engineering to improve the species and its ethical considerations, the Mechanoids(who aren't always running about in a bloodthirsty rage when there aren't any humans about, but who are, in fact running their society as peacefully as any other species) are naturally worried about what impact it might have on their essential 'spirit' or "Mechanoidness'....Sure. they can engineer an even better Wasp or more aggressive Battlecruiser, but if they do so, are they really doing themselves any favor? They might create a caste that's TOO specialized and TOO eager to go off the bat on a killing spree...and they have enough problems already with the twitchy Wasps and single-minded Exterminators. Or, they might inadvertantly create something that may decide that a better use of its talents is exterminating the entire Mechanoid species as a challenge...Having already survived ONE apocalyptic civil war, the current generation of mechanoids figures that any sort of continued deliberate evolution will be in small increments, carefully monitored, and in response to specific threats like the Mechanoid Civil War. Small changes like a few points of extra armor here, or a slight enhancement of the nueral chemical controls on aggression are doable and controllable, but creating a new caste that has nothing in common with the existing castes, and thus harder to diagnose/monitor from a set of existing behavioral/performance specs would be a massive undertaking fraught with hazards.
If the Mechanoids need anything for a specific, narrow focus task(like killing EVERYTHING in a specific circumstance), it's much easier to create single-use/purpose robot drones that are easier to create and control....Generating or modifying new (sentient) lifeforms of their own ilk is too dangerous without due consideration.
Check in again in another 50,000 years....
-------------
"Trouble rather the Tiger in his Lair,
Than the Sage among his Books,
For all the Empires and Kingdoms,
The Armies and Works that you hold Dear,
Are to him but the Playthings of the Moment,
To be turned over with the Flick of a Finger,
And the Turning of a Page"