Editing max systems in settings.txt

The default SystemNames.txt list only has 150 or so names. Some mods include SystemNames.txt files with a whole bunch more.

Some quadrant types (like Spiral) don't look all that great with more than 100 systems, but otherwise there's no real issues with quadrants of 200 systems.

Space Empires Depot | SE:V Balance Mod

Some of the systems created have nothing in them. No stars, no planets, no warp points. So they are pretty useless until you get Stellar Manipulation techs high enough to make them military systems. Put bases with construction yards or repair facilities and just use them as parking lots for your fleets.

Or until you can make stars and ringworlds. Or sphereworlds.

Once I tried a map with around 200 systems and no warp points appeared. Boring and lame.

That's not the case (assuming you didn't accidentally select No Warp Points) but sometimes the warp point lines are not drawn if there are too many systems, but they do exist.

Space Empires Depot | SE:V Balance Mod

I think I encountered a similar problem myself when trying to make larger quadrants.

in Settings.txt
early on, the part marked "Starting Game Data"
There is the following entry

Maximum Number Of Systems := 100

Have you changed that to match the max number of systems for large quadrants?

I think if a quadrant is made with more systems than that value, the 'extra' systems will be empty.
e.g., a quadrant generated with 120 systems with the default Max Number of Systems will result in there being 20 'empty' systems.