Yep, all situations are different...
Although analysis of our aikido is very useful, and helps to polish technique, no technique is perfect. There are always ways to get out, avoid, counter etc especially when we know what is coming. After the certain 'honeymoon' period in aikido many people loose faith because they say - well I could do this/that/the other. Why didn't they think of that initially? - cos they didn't understand aikido initially.
It is very important not to think uke is like nage. As uke you do a strong, fast attack directly towards nage - the usual similation of a suprise attack esp. from someon who wishes to lay you out in the first blow. As Nage we blend.
Once we confuse these two there is no way but through competition, but when this happens it gets more unrealistic because then when someone does attacks you aggressively in the street and doesn't look for a counter etc they are too fast and too powerful for our 'competitive mind' to do anything about it.