Custom game speed mods such as Historic completely obliterate any sort of balance. They make the early game (up until Classical or so) extremely tedious as players will need to micromanage to ensure they do not completely destroy their GPT or science or culture rate. The AI almost always destroys themselves during this phase.
They magnify certain bonuses overwhelmingly compared to others: Culture and Science are literally the only things that matter, as both have a snowballing effect as you can produce those science and culture buildings much faster than they are balanced to be created. You can build every single relevant building in every city long before ever reaching the next tier or set of buildings and this leads to a horrific snowball effect for the player, who can micromanage much more efficiently than the AI.
The few games I played on historic were basically "rush 3-4 cities in decent spots, wait for classical, literally cover the map with cities" and the AI couldn't respond to this.
If you want massive wars, though, try using a mod that caps techs early - I played a domination match with tech capped at the end of the Industrial era, and it was incredibly fun once the AI caught up to me.
And infrastructure is what is vital for this game. If anything, it'd be more prudent to lower unit hammer costs compared to buildings, rather than buff buildings, but this is another change in favor of players who already manage armies much more effectively than the AI (as much smarter as it is)
