Great post Dogeatdog!
Yeah i certainly agree VC and SA are actually better games, the progression from III, to VC, to SA was immense. I don't think we'll ever find a better gaming Trilogy.
I agree with about the Radio Stations, Flashback was always up there with my favourites too. Obviously R* were limited with music rights on III, i feel like VC's soundtrack was revolutionary for games at the time. I'll always remember jumping on the Faggio for the first time and Bille Jean playing, great memories!
Yeah the missions aren't too bad once you get to know them, i learned a lot through Speedrunning and how to do missions fast, and manipulating certain aspects of them. E2G when you don't know the map really is a toughie, kinda easy when you know where the Stalls are, and have done the mission 1000 times

Kingdom Come, oh man "come to daddy, special delivery"
I will add to the dislikes, and that's how if you don't do the missions in a certain order you can easily lock yourself out of 100% completion. I feel that was a major flaw actually. Also yeah the hostility towards you, Fort Staunton and Portland being the worst (Portland after you kill Sal) make Paramedic for example as good as impossible to complete. The best tip being, get as much of the side stuff done asap.
100 Taxi fares is a little excessive, as is 20 Vigilante and Firefighter missions per Island. Though there's plenty of tricks in Speedrunning to get over them. Skipping Taxi all together really is handy for 100% Speedrunning.