Ambientweet shows just one tweet at a time. This is a deliberate design decision, which allows for a minimal user interface. This, in turn, means that the text can be bigger and there's no need for extraneous clutter like toolbars or buttons whilst you watch the twitter world go by.
You can use Ambientweet to post, reply and re-tweet, so it's perfectly adequate for adding to your stream and responding to what you read. What it doesn't include is lots of complicated functionality for viewing profiles, following people, managing lists and accounts, and so on. The Twitter website is great at that stuff, so why try to replicate it?