A LoL/DOTA-style MOBA or RTS is pretty ambitious using these technologies. I think you are going to run into two major issues:
Message rate limitations: In my experience, trying to send more than a few messages per second to a php/MySQL server will quickly overwhelm your server, as it has to receive the message and read/write to the hard disk synchronously every time. In something like LoL or a traditional RTS, each player might clicking several times a second, and each of these might generate a message to the server, quickly overwhelming it. This is just for a single game. If you have 10 games going on simultaneously, each game might require its own server, quickly driving your costs through the roof.
Lack of an integer data type: Because of the large number of units involved, MOBAs and RTS games don't try to send the entire game state over the network. This would require gigabytes of data every second. Instead, they only send player inputs, and each computer is responsible for computing the results of all of the inputs. This requires a deterministic computation. To do this, you really need to be using integers instead of floating point numbers. Because it runs in a browser, you don't have direct access to integer data types in Construct, and this will introduce errors and inconsistencies between different player's computer's versions of the game.
Hi and thanks for the input. Right now, what I'm looking at is a 8v8 moba. Each of those has speed and direction to be determined. Each of those can also fire up to 8 bullets each, 1 'direct fire' weapon and one semi-tracking weapon. Naturally, other data will need to be kept track of such as hit points, a shield and energy. While most of the time it won't have all of that on any one client's screen at a time, it is a possibility. Now, I know for a fact that UDP can keep up with this kind of data as it'll be a variation on a much older game that used UDP. What I'm concerned with is whether a NW.js game server and a C2/3 Web client can handle this kind of information using the multi-player plugin. Unity could do all of this with a lot of power left over. But creating a win/linux/mac client for it and writing code in c# is a nightmare I'd rather not deal with.