Well, the using of armed combat drones is quite recent, so a combined arms tactics of drones and conventional weapons may be in the works. As for legged vehicles, the only place such weapons could be effective is urban terrain, but they may be only useful against irregular forces, which rely most of the time on "Technicals"... until one steps on an IED.
If the mecha is a remote-operated unit, then there won't be much problem, but if it is manned, well it may lead to suffering casualties.
But I am pretty sure that in urban place, you won't encounter anyone that uses logs as weapons...