OCS is stuck on low-res monitors without a scan-doubler/de-interlacer.
ECS and AGA have programmable scanrates but the max pixel clock is 28.6MHz NTSC or 28.3MHz PAL. So you get 720x480x60hz on a standard VGA monitor, plus a bit of overscan maybe. Any higher resolution than that will have to be interlaced or trade off refresh rate. For instance, with a medium resolution arcade monitor (24KHz) or an old EGA-compatible analog monitor (21.8KHz) you can get roughly 800x600x72hz interlaced or 1024x704x60hz interlaced.
