The biggest weakness of power armor is its overland speed. Like infantry before it, war planners are always looking for ways to move their boots on the ground quicker and more efficiently. The Cosmic Era has been watching the escalation of power armor infantry transports and almost anything is worth a try at least once. There are already a number of mecha that are designed with power armor in mind, having hand and footholds for troopers to ride the mech like infantry of the past caught rides by sitting on tanks and other vehicles. The Roadrunner takes this to the next logical step, the mech is designed to specifically carry and deploy power armor into the field and provide a modicum of fire support.
The Roadrunner is a light mech with modest armor, minimal weaponry, and high mobility. The torso is designed to more easily accommodate power armor, and it is much easier to lock onto that improvised footholds on other mecha. Structurally the Roadrunner uses many common components with the Cicada medium mech, but the reduction in armor and weaponry allowed the mech to be scaled down, use a smaller reactor, and be cheaper and easier to produce. The production model Roadrunner is armed with a handful of short range lasers, machine guns, and a short range missile rack.
The Roadrunner is faster and more maneuverable than all of the tracked and wheeled power armor carriers, and is better in a support role due to most mecha being able to take a more substantial beating than most light vehicles. Mecha mounted power armor units integrate regular combat mecha and recon mecha into their formations for highly flexible and capable combined arms units. Compared to skyborn transports, the Roadrunner is slower, but it is also generally cheaper, and since they dont fly, having a roadrunner shot down doesn't automatically take out the power armor troopers. Aerial transports that get shot down tend to not have many survivors.
The Roadrunner, and similar power armor transport mecha, are solid state, and have no bleeding edge tech in their design. Production is simple, support is no different than for any other mecha, and as basic production mecha, they are pretty much average for maintenance, support, and usage.
Depending on unit: some units will have the Roadrunner or similar transport mecha dash and drop the power armor troopers then retreat. Others will advance, drop the troopers close, and remain with them as fire support and fast evac. Roadrunners and similar mecha are not intended for anti-mech operations and if confronted by main combat mecha they as a rule retreat and hope their high speed can get them out of danger, while their troopers engage, or also hide, depending on what has stomped into battle.
There was a second attempt at a power armor transport mecha, a four legged walker variant. This was much more popular with the test crews, but hated by planners and builders. The quad mecha was nowhere near as fast as the Roadrunner, and was larger, more heavily armored, and more heavily armed. The power armor was carried inside the 'belly' of the mech and would power drop into combat, while the walker stayed with them providing assault gun support.
The walker proved generally inferior in combat situations as it was still not designed for mech vs mech combat, and lacked the roadrunner's high speed. Crews liked the heavier armor, but this was only useful when the mech was in its intended infantry support role, and once spotted the armor was not enough for resisting mecha, ground attack aircraft, and guided weaponry.