Hello,
I am here as well, because I've started researching the innumerable issues I've been experiencing with 4.4, that did not exist in 4.3.
Since 'upgrading' to 4.4, I am having various problems with Import. These include simply hanging, crashing LR altogether, and losing Sources. Once the Source (e.g. a camera card or my iPhone) are lost from the Sources list, Sources as a whole becomes unresponsive. The only recourse is to terminate LR (because it's then unresponsive) and start again.
4.3 was very solid, I never crashed it. With 4.4, I am seeing multiple abnormal terminations daily, application lockups/unresponsiveness, and niggling issues. I regret installing 4.4.
Simon, you're not alone.