I could come up with a wish-list that the currently existing backtesting programs/sites don't cover.
Main two things I miss:
- Multi time frame testing without back-painting. So if the main chart is 5M but you use a signal from 15M as a filter the data coming from 15M should be the data as it was on the close of the 5M. Not of the close of the current 15M nor the previous close of the 15M
- Graphical user interface to build a strategy instead of some code language.
I have been looking for the combination above for a while now, but can't find it. Maybe in the REALLY expensive high-end solutions, but we are talking retail budget here.