While the air and sea combat and exploration in GTA V was fun in parts, it still falters as the weakest weapon in the Grand Theft Auto arsenal. If you look hard enough there's some interesting ideas hidden in the current game, they're just criminally underused. For instance, jets feel and respond phenomenally, yet they don't appear once in the main campaign. Tying these different mechanics together could provide amazing results. Imagine having dogfights in the air as Trevor while Michael attempts to pull off a heist among the chaos below. Combing elements like this could have made for a fascinating juxtaposition from a gameplay perspective, and would have been a brilliant way of showing off the benefits of having more than one playable character. GTA V attempted occasionally to implement missions like this but it never really felt like Rockstar was fully confident in doing so. While the air and sea aspects of the game aren't bad in and of themselves, they just need a bit more fine-tuning to integrate them more seamlessly with the core land gameplay players know and love.
