I assume most people are like me and scroll over the ticker names. I realize the trade icon shows up when you hover anywhere on the row but it would be much, much faster to trade if it was in the security column just to the right of the ticker.
Waiting for the trade icon to show pop up text is too slow for me. You wouldn't need that text if it was on the left.
And I don't think it would be obscured by the tickers's own pop up text. in IE that text covers the stock below my mouse.