Played this a bit, and the dynamic is good, there's an excellent mechanic here.
In fact, it's very similar to and old X11 game named "XBattle" I used to play. ftp://ftp.gwdg.de/pub/x11/x.org/R5contrib/xbattle-4.0.README
XBattle has many, many parameters you can tune (growth rate of "armies", decay rates, as well as persistent movement on production, etc.) All of these can be combined in different ways to get some really great game variants.
I liked xbattle even better because while it has a very similar mechanic is also rewards strategy.
So for xbattle if 100 armies fight the enemies 25 armies the losses are mostly on the 25 army side. Additionally if you attack an enemy from 3 sides simultaneously that's an additional advantage.
With generals.io it's always just even losses on both side, so it's basically about production and finding the queen. Not so much about defense, or more complicated strategies.
In fact, it's very similar to and old X11 game named "XBattle" I used to play. ftp://ftp.gwdg.de/pub/x11/x.org/R5contrib/xbattle-4.0.README
XBattle has many, many parameters you can tune (growth rate of "armies", decay rates, as well as persistent movement on production, etc.) All of these can be combined in different ways to get some really great game variants.