Stupid story compared to IV
I think both are all right. IV attempted a more serious, grounded tone (in comparison to SA) while V went back to the San Andreas tone of causing a massacre at a construction site and burying the foreman alive in his own shit because they catcalled your sister.
What? I know the car handling changed completely and was made more unrealistic, but that was for the better since it makes driving more fun. Air control and the ability to flip the car is great, realism be damned.
Was it even changed from IV? And it's such a miniscule detail in a GTA game, who even uses melee fighting?
combat that felt like pillow fighting
What? IV's combat is literal popamole, designed for cover shooting since that was the hottest trend at the time. The combat in V is more mobile with higher FOV (and faster movement speed?) while aiming - in IV I used cover the entire game because it felt necessary, whereas in V I barely ever used it because it didn't feel like a must anymore. You could just run and gun all the time.
Enemies in V are also more squishy, leading to encounters where you quickly dispatch a whole lot of them where in the same situation in IV you would only face a few. Headshots are also always instantly fatal in V (IIRC) whereas armored enemies require 2 headshots in IV.
I found Trevor, Lester, Michael and his family, Simeon, Lamarr, Madrozo etc. very likable and in the same vein as previous games.
mostly emphasis on multiplayer to the detriment of single player
Utter nonsense. Singleplayer and multiplayer are two completely different things, and the singleplayer part is absolutely immense. This isn't some slapped-on singleplayer campaign to a multiplayer shooter. We're talking 50+ hours of missions that often feature one-time gimmick mechanics (something I am not a fan of, but it really shows how much of a development emphasis was put on singleplayer).
There's also the ambitious three player characters thing (which I think was a neat idea but it did cause problems) which makes your claim that multiplayer somehow hurt the singleplayer ridiculous.