Context Menu and Goals
First, I'm not a designer, so the UI can of course evolve (e.g. a modern flat design ;-))
It would be great to have a context menu with different options. E.g. setting multiple TPs, SLs, Scale Ins/Outs as seen in the picture. The value in the middle should be context sensitive (Scales should show percentage, TP/SL ticks etc.).
The chart should show the multiple TPs/SLs on the chart. A little bigger than it's now, as sometimes it's hard to read. The labels should also be movable horizontally, as they sometimes clutter up information.
A nice feature is to have donut charts for daily/weekly/whatever timeframe tick/cash/whatever goals and other information like P/L or winning/losing trend percentages. Donut charts are great to visualize that like in the backtester.
Skins/Themes should also be applicable.
Access to the elements through the API would of course be awesome, so something like this can be done (but maybe that's just me ;-)):