Using You tube video for SEO warning

Hi Guys,
thought you guys might want to hear my story as a bit of a warning.

I was ranked number 2 for a 2 word keyword that provided 1000 searches to my article per month.
However I worked out that number one article received 3000 searches per month.

So, I read that adding a youtube video to your blog almost guaranteed getting that coveted number one position, so that's what I did and voila, number one position withing 2 weeks and now 3000 per month traffic. All was well for 3 months until I noticed I had suddenly dropped to number 7 on Google.

So i checked my website as I thought something must be seriously wrong as I hadn't moved out of the top 2 in over a year. Sure enought, the video that I added was no longer available and as such my embedded video was not working.

I presume Google sees this as a bad user experience and acted accordingly, hence the drop down the rankings.
I have since found an even better video, but knowing that quite a few videos are eventually unavailable, I am thinking of simply removing the video altogether.
Google have raised me to number 4 after about a month, but doesn't seem as keen now, even though it's really a more relevant video than the old one.

Just thought it might help someone in a similar position.