The great thing about Aikido is it's explosiveness. We can just charge people down. I think of it like this: BJJ shoots for the waist and below, Aikido shoots for the waist and above.
I use the power of the charge to pin my opponents arms into their body and force them back or I charge in and open up their guard and go for sumi otoshi or uchi kaiten. It's over in three seconds flat.
You're a striker? Great, I weigh 13 stone, I'm charging in and though you with my guard protecting my centerline and reaching for you and making atemi, good luck stopping me with one punch, if you even clock on to what's going on in time.
The trouble with Aikidoka is that we fight like westerners on the whole. We want to stay mid-range and grind our opponent down. We don't like the idea of ikken hisatsu, of risking everying on one decisive attack japanese stylee and so we get chewed up by those using arts that are suited for mid-range fighting forgetting that those arts get chewed up by close range fighters, like Aikidoka.
Seems like you are counting on your size to win encounters. Remember that a bull fighter fights bulls way bigger then they are. A good striker has no problems circling, hooking, and keeping distance. While it is true that getting in close may give you an advantage, you make it seem like you are advocating just running at them with your hands up. My small experience in boxing tells me that is universally a bad idea. Further more this would need to be something practice often against someone wearing some boxing gloves doing his best to ring your bell. Otherwise how do you know that you are properly defending yourself as you move in and that your opponent can't just step off the line and drill you with the full force of your body momentum and their strength right in the chin with a nice hook (ever walk into a jab, it's way worse then just getting hit with a jab). This is of course all assuming the person you are about to rush knows he is in a fight. But I'm not thinking you are advocating bum rushing people who mean you no harm?
Although personally, if I was going to fight in close, I'd prefer mauy thai mixed with judo. I see aikido as the range between distance striking and the clinch. Which is of course commonly called the trapping range.