Nice write up on this! From the bad news list, I mainly wish day and night cycles were making a return, but with the modding support, maybe it'll be fully possible with mods at some point. Also wish we could toggle upgrades, but once again, mods.
The good features outweigh the bad from the sound of it though, imo. From the good news, it's such a small feature, but I'm glad we can import our character from SRTT, and most the VA's are returning too. The weapon skins/costumes are something I never thought of, but I love the idea now. (Especially the Super Soaker haha) And of course mod support, still flipping over that.
Only other thing I'm wondering about is the DLC issue. I got the SRTT Franchise pack on Steam, and bought the remaining couple DLC on sale, (I'm a completionist, OCD or something I guess.) but I hope SRIV won't have that much, well, content wise maybe but I hope it's more bang for your buck. Hopefully Deep Silver is more in line with that than THQ was.