well.. a lot can be gained from cross training. Depending on the style of aikido something will fill the 'gaps' better than others.
For atemi undestanding: karate or another striking art
For understanding center and how the japanese sword moves: iaido or (to a certain extend) kendo
For understanding the jo.. well.: jo do of course
For ukemi and balance: judo
For centering, balance and softness: tai chi
The list is endless and I have only mentioned a few of the martial arts that I know of. Many more could be added in each category, and to a certain extend they all teach the whole package - depending on how, where and with whom you train.
The trick is not to get the batter mixed up before each ingredient is ready. You can utilize something gained in one budo if you reflect upon it in a different context, but reflection requires time and effort. The risk is you get ahead of yourself. So.. by all means.. go train something that will help you blow some steam.. Soccer, baseball might do the trick - but if your heart is set on a different budo, talk to your sensei about it. Maybe he/she can give you good advice. And then do so, but keep your focus on what you perceive as you main budo.
Maybe you will feel the urge to change into something else - maybe you will fell that it lacks what you like about Aikido. but go explore. It will be good for you as long as you limit yourself to a few budos, and don't fill your head with more than you can process. It is a common mistake when you are young.. (and at my age as well one might add
)
Have fun - that's the most important.