To be fair their reputation on the Amiga can be hampered through emulation and defaulting to PAL. Most of their stuff is playable in NTSC. It's just sad that these magazines were begging and screaming for them to "someday discover the blitter!" and they never did discover it... Everything is going through the CPU because that's how it was done on the PC, but the Amiga didn't need a 25mhz processor because it had all these other chips which operated independently, but you gotta use them!
The ultimate F-U to Sierra was after they abandoned the Amiga in 1993, another company bought the rights to port King's Quest VI to the Amiga and they did what Sierra programmers seemed to think was impossible... Make it run well. If Sierra hadn't been the ultimate of cheap companies they would have seen what they couldn't do and farm out the games to those who could, like other companies did. Unfortunately that would mean paying for those companies to port the game, where with King's Quest VI it was Sierra getting paid... Oh well, put them on a composite CRT, upgrade the processor, install them to a hard drive and run them in NTSC, and they're still good games.