It is really hard for me to fathom why the play head on the timeline is useless for seeing what's on the stage at a given point. Having come from the world of media production into the world of instructional design, I find it gob-smackingly mind boggling that SL can't do this and that after what, FOUR YEARS, this feature is not here. Every single media creation or playback program I can think of does this.
It was so shocking that I got my company's IT department involved as I was sure it was a problem with our older laptops. Oh, and I really like the way the support department doesn't bother to respond when asked about this. Gives me a great sense of confidence in the product we just purchased for my company's group of 10 developers, and that we'll be able to get any kind of support.
You owe us an explanation. Not "Oh well, we'll put in a feature request." After almost five years, I think your community is well past believing that, and believing that your development team has any intention of addressing this. Otherwise, something so obvious, so frequently called out, and so blindingly obvious would be addressed. That's how it works. Just ask Adobe. So how about y'all come clean as to why we're made to suffer this way. You do use your own product, correct? And understand how negatively this impacts your users' ability to accurately create what they see in their mind? Quite the dirty little secret you have. And being a new user, it seems like quite an insult to your users as well.