Collin touches on a sensitive subject for me.
Throws onto concrete, against cars, lampposts, parking meters can definitely be devastating. Having just done 5 years of aikido, I can also say a lot of throws in the curriculum will not be as easily appllied as in the dojo with a strong, non compliant oppponent on the street (my opinion).
There is an old maxim in aikido, still referred to by the really old (and soon to be passing) guard of the aikido world like, Saito and Nishio senseis (we recently lost Shirata and Shioda), that atemi (strikes) are in 90% of aikido techniques. (This is the converse of saying throws are inherent but hidden in many Uechi techniques.) The reason that atemi SHOULD be in 90% of the techniques, I think, is the recognition that throwing a skilled opponent is a very iffy proposition unless one has connected a good strike to disrupt the balance and the "sober" state of the opponent. A good strike may even take the opponent down and out, precluding the need for a throw.
The other 10% probably include, as Collin indicated, an opponent rushing in with great momentum and/or strength. In this case a strike may actually be counterproductive by stopping the energy that can be used for a quick powerful throw. Anybody who saw the heavy weight match between Ethan and Josh Wiseman was given a good example. With Ethan coming in, Josh grabbed, fell back and threw Ethan over him in a classic sutemi (sacrafice throw). Ethan, with prior judo training, knew enough instinctively to tuck his head and roll. Somebody else could simply slam head first into the concrete, resulting in a fractured skull and/or neck. Definitely an effective way to end a fight.
As I see it, there is growing problem in mainstream aikido these days in the movement away from the simple atemi for the sake of "flow", beauty and I believe a mistaken notion of DO. Quite simply, atemi is seen as abrupt, brutish and not in keeping with "harmonious" (and some complex) technique. Atemi is not practiced, nor encouraged and rarely demonstrated on most aikido mats today. Yet, there is a delusion being perpetuated by significant number of teachers and students themselves, that they are still practicing an effective self-defense art. Delusion is not part of DO in my eyes.
As in a lot of marital arts dojos, the pursuit and the granting of rank seem to more important than anything else for too many. If one doesn't test, one can gets a quizzing from fellow students and eventually from the instructors. One of gets a sense of not being part of the game and the culture of the dojo. To stay, one has to make some accommodations or be a pariah of sorts, uncomfortably looked on and related to by others -- regardless of one's skill levels.
Several months ago, I tested for second kyu. My partner was someone who worked with me a lot and knew my attitude and "style" of doing. He was a great uke, attacking at full speed and full power. After each throw he would jump up and rush me again while other folks took their time, set up and sort of waltzed in with their half hearted attack and fell with a half hearted throw. I implemented the maxim -- 90% atemi -- consequently giving my uke a black eye because of the speed we were going at. My uke took it and kept going even as his eye swell and blackened on the mat. In randori with multiple partners, again, something I ingrained regardless of the prevailing culture, strike first and throw as hard as you can. My partner felt very comfortable about what we demonstrated and the responses by some of my fellow students -- "remind me not to uke for you. Heh, heh..." Several black belts, including instructors, opined that I was way too rough, that I should have "calmed" down. Both my partner and I were "puzzled" to say the least.
Perhaps, coincidental, but a week later, an edict came down to the early morning class, of which I and my partner were part of a small cadre, that we were to no longer do "free practices" on our own after classes, that a instructor must be present. Two students, me being one, who were given keys and the responsibility of locking the dojo after the last student were told to turn the keys in. Yes, coincidental, perhaps, but my approach to aikido certainly did not jive with the prevailing one. After five years of 4 to 5 practices a week, I submitted my request for a leave of absence. Some of my cohorts and those who started after me are now busily preparing for their dan test... Oh, that black belt goes so well with the black hakama.
Oh well, enough venting. Hopefully, some of this post is related to the thread at hand.