Oh, you aren't kidding. Mean Streak (or as it was also called Mean Screech) was not a good coaster from day one. Interesting layout that made no use of the speed from the first hill. It got worse over time and was just vicious. Son of Beast (perfect initials but for a slightly different name) - it was terrible with an extremely boring layout. It's the only coaster that I have been jackhammered on so bad that I basically had to quit riding for the day. Motion sickness sucks but that coaster literally literally made you feel like you had been worked over by a gang armed with aluminum baseball bats. Those two are the worst coasters that I have ever ridden, bar none. Unsurprisingly, Son of Beast's designers, GCCA, also designed The Rattler which was also a bad coaster. Youtube it and watch the first drop track sway as the coaster goes down.
I don't know if Gwazi got that bad towards the end or not. Again, I rode it back in 1999.