AR was perhaps best aliens game we've ever been given to date, although the aliens were still very tiny in that game too.
Believe It or not the size of the aliens in all videogames is, If not the greatest, maybe one of the biggest problems. Do you really believe all that bullshit that has been thrown over and over again for many years by many people that insist they need to be small for gameplay purposes, or classic hitboxes lolexcuses?, making them based on their stunning size is a must too. Until then, you can make them as intelligent, or fast, or whatever you want..., you will still laugh at them as you meet them head on and realize your even taller than them.