If someone is concerned about getting to the end of the technique so much that they are off balance, muscling and otherwise not doing aikido: SLOW DOWN!
If slowing down doesn't help and the individual is still muscling, off balance, etc. Have a senior student be uke, and let that senior student totally screw him/her up.
If I totally botch a technique I expect my Uke to stop me and help me correct it. When something doesn't feel right, usually something is wrong.
Help each other learn. I've told my partners often, "We're doing something wrong, but I don't know what, let's ask sensei."
Iriminage isn't called the 20 year throw for nothing.