Looks like we all have this problem!!
Nobody in mt5 going to doanything about it?
Here my two cents. I know a bit about both mql4 and mql5 since we created two graphical environments to generate eas and indicators for MT4 and MT5. This is hard core code generation so we really learned both languages. MQL4 is a nice and easy language. MQL5 is also nice but not easy. It's more powerfull but the learning curve takes more time. Once you get there, you will be able to create better strategies. We thought about creating a tool to do the mql4 - mql5 migration. First issue we faced, you cannot migrate mt4 eas that use hedging. There is an article about a possible solution but it is too complex. Second issue, the way you manage the index for the indicator buffers is different, so you can't just replace the old command with the new command. We did lots of testing and there are many corner cases. It really depends on how the indicator was written. Unfortunatelly coders have different styles which does not help. Creating a tool to do the migrations is time consuming and at the end it won't work for all cases. Still, some human intervention is required. The best advise, learn some of the mql5 basics and then you will be able to fix the code generated by the program rewriter.