Dreamcast and PS2 are about on par with each other as it Gamecube I wouldn't even say you can handle Dreamcast emulation though :/
Don't know what plugin you are talking about the plugins that are in 1.8.0 are available for 1.5.2 the only ones that are not are the hard coded CD plugin/s and the default sound driver that is not a recommended most the time but works much the same as the rest did that got hard coded into the older version from 1.7.0 they did break the disc swap in 1.8.0 the CD plugin was fixed for disc swaps, it was never a major issue as at the time all you done was use a Virtual CD drive as the swap worked for disc drives just not for disc images in 1.7.0.
Just sounds like you never had the older versions setup correctly to start with.