Something like
this Metatrader EA would be awesome. You mark your SL and your LMT/STP entry, and it calculates position size and submits the order automatically. If you move your entry, it recalculates. If you want to enter on a MKT order, you mark your SL and then when you hit buy/sell it calculates position size based on bid/ask at the time you hit the button (with a configurable buffer to allow for slippage). I was going to try and port it to MW before I stopped using it.
Incidentally, Motivewave has
this strategy which goes about halfway, but afaik it does not calculate position size for you like the above linked metatrader EA.
I have a love/hate thing with Quantower. It is very pretty, drawing tools are reasonably nice to use, but it has quite a few bugs and seems to lack strong QA when new releases are made. But, it's one of few platforms that supports both Oanda and IB (albeit poorly with IB), and I need both of them. That's the main big showstopper with MW for me - lack of Oanda support, and this symbol mapping thing with IB.
I used Overcharts (and Multicharts) for a little while before settling on Quantower. I really wanted to like Overcharts because it is rock solid. So stable, and so fast. But it had too many things that made it cumbersome - the biggest annoyance I had with it was a 100 object drawing limit which I always hit part-way through my day. It sounds a lot, but I use a lot of little labels and symbols when I trade (like individual numbers at 8pt counting entries, or little lines to mark microtrends, etc), along with the usual trendlines and notes, etc, so it adds up quickly.