I can agree with the 2 for 1 GC/EC exchange as they're earned through the same means.
MVP and Mystery coins are a completely different currency, and shouldn't be exchanged like that though.
The GC shop was supposed to be updated bi-monthly to be honest, when it first came out. It was updated 1 time then never touched. I don't even know how to manage the items myself, never bothered to look into it.
The EC shop is also pretty dated. Ultimose has been trying to get ideas for some new stuff, but I'm not sure is anything is sticking.
MVP shop is pretty legit since I made the gun set, but eventually that will be obsolete as well. Especially with the ridiculous amounts of MVP coins being distributed... I originally had it at 7 per week. But last week somewhere around 20~ were given out.
Iunno...
Use this thread to pitch some EC/GC item ideas, I'll check on it now and again.