Stox,
Best wishes towards your effort. While the less easy path, I would encourage you to develop a TA package if you have the resources and the staying power. It is always better to 'own' the API than to play second-fiddle to somebody else (of course, it will be built on other APIs). To this API, you can plug-in data sources of choice, add a customized UI on demand, provide a trading interface, add your trading system.... just thinking of a biz angle of tying up with FT for Odin (i.e. ride on a broker). But this is digressing.
As AW10 and Raunak have already mentioned, the feature list of Ami/MS would satisfy most user and be hard to top. Here are some I would like:
- Time axis of charts: a smooth transition for time frame. Assume a slider movement that could give 1M, 2M, ... 1H, 2H ... 1D, 2D, ... charts. This would reflect in the charts / indicators. Existing TA packages treat these very discretely with keyboard shortcuts/menus/icons, etc. In some way, this blurs the distinction between intraday/eod.
- Time axis of charts: a convenient way to look ahead. A simple example, wanting to view where trend lines intersect in the future.
- Price axis of charts: A fixed percent option. Say, for a fixed percent of 30%, a stock @1000 would show charts in the range 900 to 1200, a stock @400 would show the range 340 to 460. This makes is visually easy to distinguish stocks that have similar price shapes but relative differences in range. Current TA packages tend to fill the vertical space with the stock's actual price range.
- Charts: Everything, bars / indicators / titles / studies in layers (as in Photoshop). Whether one wants to see BBs behind or in front of bars is upto the user. View/Hide is controlled in the layers.