This is a topic to discuss the Wiki
My English is not that good, but “last call optimization” is rather ambiguous. Is this the last time we do call optimization or do we optimize the last call?
I have never found fault with your English 
, but then I do not have a degree in English, so I don’t see a need for it is not that good. I am sure if others did not know it was not your native language, they would not know. My English could be better but my spelling is horrendous.
Truthfully I never though of it as being ambiguous and I have no problem changing it to last-call optimization where it is last call optimization.
I will wait to other have had a chance to read this and reply before possibly making a change.
I know this was a year ago, but I thought someone should point out that your understanding of English is perfect here, and the hyphen serves exactly to disambiguate the phrase. (Similarly, a big-box store is likely not a big box-store.)