I have been into MT4 and MT5 platforms for forex trading and have not experienced rich features for trading environment in any exchange than MT4 and MT5. In my opinion, most online platforms and crypto exchanges are trying to copy MT4 and MT5 and no other new innovations (this is just my personal opinion based on what I have observed and I am glad to be proved wrong).
You're probably right about the "online" ones, so hard to prove your wrong there. However, if you widen your scope a bit, we are actively working to build a different kind of platform that's more client-centric (referring to the device not the user). We're still in early stages and are not attempting to build something as elaborate as MT, but we are looking at the problem differently. We are focusing on the strategy-authoring experience. It seems that the majority of options revolve around scripting something in MQL or some scripting language, very basic controls, or going for a mostly automated system and hope for the best. Instead, we're trying to create a sort of "debugger" for trading strategies.
If you, or anybody else, would like to follow our progress, try out what we are building, and/or contribute ideas, just let me know.