The engine does not make the graphics, it plays a far smaller part in how a game looks than one might be led to believe by video game journalism.
The games you have listed are by hobbyists with very limited budget and possibilities. You can't "upgrade" the graphics of an engine. Only open up new possibilities for a better workflow as in shaders / lighting (!).
What makes game guru games look dated is mostly the lighting which really needs to be updated dramatically and many smaller parts of the workflow. You are free to try unity or UE, in fact I highly recommend you do so to experience what actually goes into a game and even though these engines are FANTASTIC, they don't do the work for you.
The graphics you want to see as in Battlefield or COD is mostly due to one thing:
Art direction and skill in these studios. Especially call of duty was notorious for using old tech until recently. There is a good reason why the production of these games swallows millions of dollars.
But to be precise:
Quote: "but the mechanics of the game are very dated with the enemies looking like something out of the 90's and their movements are not realistic at all."
Player movement and basic game mechanics is something that Lee can give us more freedom with, this really is something where we need more freedom engine wise. The enemies and how they move is entirely up to the models we use and believe me, none of this is related to the engine. You could import
this character into GG if you wanted to. Just note that even prices where never as low as now, chars with Battlefield V or COD quality are expensive, especially if you want variety and GG is a steal when it comes to the amount of custom chars it brings.
In fact, if you can model better characters and give them better animations there should be very little in your way for getting them in the engine.
Quote: "Please let me know if there are plans to update it and make it more like games made with Unity and Unreal Game Engines."
No, probably not.
-Wolf