Pet System
I think a pet system like ARK's is better than the easy mechanics of spell casting. I think obtaining a pet should require some work in raising the pet, including feeding the pet.
Pets should also have a decay timer, so they grow old and useless, until they die. Also, they should have the ability to be revived a few times perhaps, in case of some people's mischief. You ask how many times, you should already know the answer for a cat, having nine lives. So large animals could have a certain number of lives.
The Ranger Class and the Specialized Class of Rangers, should more easily be able to train pets, and any wild pet. They should be the only class to be able to handle the strongest, more powerful pets. Perhaps even control more than one pet.
Rangers and the Specialized Class of Rangers, should be able to control a wild beast, for a limited duration, and raise a pet for a longer duration, having a slower decay timer.
I think its pretty cool to find a nest, den, or lair, and be able to obtain an egg, chick, cub, wolves, piglet, etc. Perhaps livestock could be obtained the same way for future mats, finding young calves, lambs, etc. There are a lot of people who play, just to farm.
Pet Specialization could be an entire class system to their self. Perhaps they could be specialized to be used as mounts, defensive/offensive capabilities, as perimeter guards, and to be able to fetch and gather. They could also be cute and cuddly for people who like ordinary domesticated animals, which means they had better show up to feed and water them when they have hunger timers, otherwise they will run off, or die.
I hope and encourage folks to imagine possibilities. Gaming is becoming more sophisticated, and I think, has to be attractive to nearly every genre that attracts the most people.
A game that is a one-stop-shop has more people on-line playing, and pvp guilds love their farmers.I have gamed with old timers, and they will farm all day long, and love it.