This is an incredibly messy question in my opinion. Aikido does work, it is effective, but if one doesn't practice it that way, it won't be any of the above. That's obvious but I don't think it's necessarily obvious to someone when it isn't effective and it isn't practiced that way.
I was recently working with someone and apparently she wasn't comfortable with the speed we were working at. Tis a long story but the short version is that she wants to work slower with me and of course I'll honor her request. Anyways, after listening to her talk about how fast we were going I made one comment to her. The comment was, "we weren't going fast." Her eyes got kind of big at this point.
I think a lot of us are like this. Think about how little most of us practice punching and then ask yourself how your partners are getting better with the crap you are probably throwing at them. Or, how are you getting better when they throw the same level of crap at you? The same thing applies with kicks and other techniques. Yet, how often are we lulled into thinking our skills are better than they are because they work against the out of shape 44 year old guy attacking us in prescribed format? Probably almost all of us because that is the world we operate in.
I remember working against a Kendo guy (he was really good) and I thought I would have a bit of an advantage because I'd done some Aikido work with the sword and he didn't know that. I never saw him move although I heard him. He was yelling out the points he struck. It was brutal. Sure it was a sport but it was at a whole different level than I was used to. In most cases, skilled attackers will be at a whole different level than what most of us face in our regular practice unless we train for it.
Anyways, enough rambling, but let me add that the only way I know to deal with this is to cross-train in as many different arts and dojos as you can to get different perspectives. Or, find a very, very, very skilled teacher who probably did the cross-training for you.
Oh, and I'm just as guilty of these things as anyone else.