Thanks. This has already been registered as an issue: bugzilla:24156: Messages of log entries should support GENDER.
I see this issue is about eight months old. Are you going to do something about it soon? It's pretty important thing to do.
I'm sorry it has not been fixed and I agree it's important. However the task is quite a big and I don't have time for such things now.
The log class now supports it, so that's a good start. It would probably be a good idea to create issues in bugzilla: for each log and each extension that has log entries, and then add those to a tracking bug. It's a lot of work. No one except Niklas has so far invested any time in converting log messages, as far as I know.
This is an excellent opportunity for volunteer development. I don't think the Localisation team will make a huge push here soon.
I could look through all of the MediaWiki and extensions messages and note the ones which need GENDER support. After that, I would create a bug report on Bugzilla. Yeah, I know there are 24.000 messages, but I can give it a try. If that's what you need, of course.
For log events we can probably grep the code, which is much easier. So a list of what should be done is relatively made available easily. What is harder, is getting the actual work done. We need volunteer developers for that. If you know any that care about this area in particular, please point them my/our way, and I'll make sure that person will be trained so he's up for the job. Intermediate PHP skills and some familiarity with MediaWiki code would be nice.