There is a couple of things that is important when dealing with automated trading.
1) Ease of use – The MT4 platform offers a good debugger platform and MQL4 programming language that is similiar to C programming. This ride onto the trading chart easy and lots of graphics and word to display on it to show your analysis and progress. The many programming features enable beginer and expert to code trading strategy into automated coding.
2) Trading strategy – No automated trading is complete without a good and profitable trading strategy that works on designated currency pair in single or multiple timeframe. The strategy should include entry and exit requirements, money management, stop loss policy, password/account protection, spread resistance, technical or fundamental analysis, server busy/free checks, support memory retention or program continues after reboot or restart.
3) Simulator – The platform must be able to perform simulation on pass history data and summary of
the simulated result to show the performance of the trading strategy. This is very important to debug and fine tune the strategy to achieve max profitability.
4) Coding support – The last and most important is the support for the platform, codes and time usage availablility. WIthout future support to run on future OS and programming language, the automated trading software will be obselete in time to come. And the broker support for the trading platform is equally important.
In summary, the platform for automated trading has to be easy to use, a profitable trading strategy, simulate to test historical data and coding support including broker server.