Well, thanks for your replies.
after looking into allot of programs and trying a few I realized I don't have any other choice then to learn one of the complicated ones, I went with after effects.
though aftereffects isn't a video authoring program per say it is the most flexible program I found.
all other softwares are rigged when it comes to manipulating videos. in ae each video is like a single jpg, easily moved, scaled transformed etc.
its easy to add drawings lines, markers and text and make sure they follow the same point along the presentation.
it actually answers all my requirements except the simplicity issue.
well, sometimes you need to work harder to get your desired outcome.
thanks all,
and if you're looking at this thread because you want the same thing, try AE. its photoshop for video.