LINK The LIST of mods for 1.6 is growing to make the transition easier. I have updated to 1.6 and happy with it. Maybe it is time to upgrade your myBB forum?
I recently tried out MyBB and it's not bad at all. But it shows it's a pretty new software. But thumbs up, they are doing a great work.
You should give it a try. For nothing else, at least you can say that you tried it. When my step son asked about starting a forum, I suggested that he go with mybb instead of smf,,,,,, or any other free forum software. One of the things that I do not like about 1.6, the script does not auto-embed youtube videos. Members have to click a video icon, and then copy - paste the address to the youtube video. That needs to be streamlined so its easier for people to post videos - and that means just posting the url. But at least its a step forward in allowing members to embed videos.
From here shows that they have plug ins for youtube. LINK Since 1.6 is so new,they have not yet updated the older youtube plug ins.