Now imagine, my friends, a Halo with two distinct races: the Elites and the Promethean Knights.
Let's say the Elites get in, what should they do? Well, the species were faster in early renditions, but were also bigger targets. So, how about we keep that speed boost and add it to their jet propulsion? Everything for them would be faster, including their sprint and climbing abilities. However, their sprint would last the shortest amount of time, and their melee would be a bit slower as well. Maybe their ground pound and charge would have a shorter time to activate and deploy with a bigger radius, but they'd be even more vulnerable.
Alright, let's look at the Knights. It's been proven in the past multiple times the machines are pretty dang tough and can deal a good amount of damage, so they'd at least put up a fight in Multiplayer. They have much bigger torsos, so maybe body on them would be even easier, but their heads are pretty small. Maybe their a bit slower than Spartans and Elites, but could make up for it with a bit more health and shield. Their propulsion methods could be much thinner and focused, releasing a slight orange line from the jets that trailed the Knights. Finally, what about their moves? Well, how about their melee and other abilities are the fastest, but otherwise their slow?
Well, there you have it folks, who should be in the newest Halo, and why?