When you take cover behind a wall and walk up to the corner of the wall the protag walks SO slow.
How small the map is. However, it's understandable. The first game introducing the RAGE engine.
Some useless radio stations no one likes: The Vibe, IF99(some good songs), JNR and K109 the Studio.
Lack of customization (haircuts, facial hair, tattoos, little clothing, no fat, skinny or muscle optimization like in SA)
Flying through the windshield when you crash at 40mph
Flying 150ft in the air when you fly off a motorcycle
Beta aircraft cut (Andromeda, others)
I disagree with everything except the cover system and lack of customization. Not trying to start one of those annoying internet arguments, though, so please dont get offended. Anyway, the cover system is clunky, Red Dead Redemption did it a million times better. Even V didn't do it as good as RDR, as in RDR, you can open doors and smash windows. However, it was their first attempt, so i can give it a slight slide. I rarely use cover systems in Rockstar Games, though, with Max Payne 3 being the exception. Map size has never been a problem for me. Admittedly, the map being bigger would be cool, but as it stands right now - they have it perfectly fine for my liking. North Alderney and Dukes are suburb, Bohan and North Algonquin are low income areas, Mid Alderney and Algonquin are concrete jungles, South Alderney is industrial. Not sure where to put Broker, but Hove Beach has an amazing essence to it. For their first attempt at the new engine, i think they did perfect. None of the radio stations are useless to me, as JNR, K109 and The Vibe all have amazing songs. I don't like IF99, but i wouldn't call it useless. Just like i don't particularly like the Death Metal version of LCHC, i still don't think it's useless. It adds variety and tone to the city, which is another reason the city itself is amazing, in my opinion. I agree on the lack of customization, though. Niko had 3 hairstyles over the course of development; a near bald style, a long caesar style and the buzzcut we have now. Add in a simple bald option, and that right there is 4 styles - the same as Michael and Trevor from V. Same with facial hair, i think it would've been easy enough to have his normal faded beard, clean shaven, a goatee and a darker beard option - all in 2D limits, though. No bushy beards or anything, 2D designs would have sufficed perfectly fine. As always, more clothes are always welcome. Muscle/fat, as you said, isn't nessasary at all, especially for the IV saga characters' backgrounds and motives. CJ was a hoodrat, going from rags to riches and trying to make a name for himself. It makes more sense for him to have the fat options. I heavily disagree with what you said about the windshield cannon and motorcycle crashes. The ragdoll physics, although a little light at times, was amazing. Bailing and crashing was incredibly hilarious, while shooting pedestrians looked very much-so realistic, more than V's (although, again, i believe Red Dead looked better than both). The crazy ragdoll physics to this day are a lot of fun for me, some of IV's charm lies in them, for me. Lastly, the Andromeda was a plane, right? As Rockstar themselves said, planes don't fit in with GTA IV's map and i personally agree with them. Again, don't take offense to this. You made some good points, and i just wanted to give my opinion on what was said.
ON TOPIC: Sorry for the novel above. As stated in it, the character customization and cover system weren't the best, and after playing Red Dead and GTA 5, it could definitely have been better.