It is hard to find an alternative to Aikido. It is a truely unique martial art that stands out among the sea of martial art styles.
I have tried to find an alternative to Aikido myself. I like Aikido but the comments about it's value in self-defense has thrown me off it's course sometimes (Aikido is hard to understand).
I had one person recommend to me to look into a type of system that is taught to mental health orderly types. It is used to restrain someone without using strikes and hurting them. But, practically you can't learn this unless you go into the field or have some lucky chance to study it somehow.
I just have not read anything yet that replaces Aikido. Judo, Brazillian Jiu Jitsu, Japanese Jiu Jitsu, and Aiki Jiu Jitsu all use the person's energy/weigh/force against them (because they all are break-offs of each other). But they aren't passive. They all are arts that mainly require aggression (or at least in sparring and competition you have to use them aggressively).
One person has already made the 1st comment to your question that people usually misunderstand Aikido. I think this is largely true. In your research of Aikido you probably have come across the contradiction (like I have) that Aikido is seen as total garbage or a highly effective self-defense system. Why the contradiction? I think it is because a lot of people misunderstand it. It is the oddball of martial arts. Just like oddballs that don't fit "normal" behaviour in society are often misunderstood and mocked, so is Aikido.
It is true that Aikido will take some time to basically be effective in (I am basing my opinions on the fact I took it's parent art [that Aikido came from mostly] Aiki Jiu Jitsu for 2 yrs. and have thouroughly studied Aikido and participated in a few free lessons). I think Aikido will be, basicaly effective for self-defense, in about 3 years (give or take a year). You do have to deal with this fact (most people unanimously agree on this fact whether they love Aikido or hate it). Aikido is basically effective when you learn these three skills good enough: evasion (avoid the attack), throwing, and the conclusion, the Aikido pin. If you can do these skills decently you are basically set to use Aikido for self-defense. I think 3 years (+/-) is what you are probably looking at to use it that way.
Aikido is largely misuderstood because of it's passive/defensive nature. The huge majority of martial arts are about pretty much seriously injuring someone (hitting, knocking unconcious, choking unconcious, breaking limbs, eye gouging, etc., etc.). So, most people are used to doing that in a martial art. When you have some martial art that is actually concerned about the attacker as well as the defender it dumbfounds most people. How can that be realistic? How can you not resort to beating someone up? Hitting them? Hurting them? It confuses the huge majority. It is a philosophy most people don't understand or like. People are more natually brutes and use force to accomplish their goals. It is a lot like the peaceful nature of most religions. It is hard for a lot of people to carry out those peaceful philosophies like the founder's intended. It is "too hard" to do. But, the key is living & breathing that philosophy until it becomes a part of who you are. Then it is more natual & "easy" to do. So, it is with Aikido.
You will have to internalize Aikido for it be effective for you. If you try to blend it with more brutal moves it won't be Aikido anymore, and probably will lose it's effectiveness. You have to live & breath Aikido's nature of peace & harmony. You have to read Morihei Ueshiba's (the founder of Aikido) intent & purpose of Aikido and how it is to be used. If you go back to the religion analogy it is the same way. You have to understand & internalize what the founder is teaching. If you blend the founder's philosophies with others you get something else and probably won't be as pure and effectie. You have to play by the rules so to speak. You have to become "passive," to use a person's energy/weight/force against them, to wait for the attack, to defuse a potentially hostile situation before it gets out of hand if possible, to want peace, to ideally minimize injury to your attacker, to focus on defense and not fighing [escape when possible], to desire harmony, all the stuff that makes up Aikido.
If someone can't wrap their mind or internalize all the peace & harmony of Aikido then it is garbage and near useless for anything. If someone try to be aggressive and streetfight with Aikido then it simply would not work. If you internalize peace & harmony, defense, Aikido, then it will be more practical and useful for you in self-defense.
So, don't give up on Aikido. I don't think you will find another martial art that fits what you want as well. It has potential b/c an Aikido black belt has undeniable self-defense skill.