Having played most of the Micro Machines titles and Toybox Turbos, I believe the physics of this game to be sound. I have especially been enjoying the ranked Race and Elimination modes. It's just a shame that there's not more people playing online. That said, I do believe the game lacks a lot of content and here's what I propose:
*Race lobby: Option to create online races and invite friends/players (choose tracks, power-ups, airstrikes, use special weapons)
*Single Player Career mode (Simply for those who want it)
NOT AS IMPORTANT:
Head to Head mode where you challenge friends/players to play for collectible vehicles (like 'play for keeps' on V3)
*More customization of vehicles
*More power-ups (it's nice to have the option of power-ups when racing with different friends. Not having Mines are a common complaint)
Though i mentioned more power-ups... I like how having only 3 gives you more of a race feel, near to the original 91 game. So for Elimination and especially Race, I would really like to see a ranked mode without power-ups, so you can rely purely on your driving skill alone (classic Micro Machines style).
Also, maybe there should be a set amount of races in ranked season, as to make it more fair. As it stands, whoever has more time to play will simply end up on top (provided they can beat AI's) It's not really fair to people who have lives to live.
Note on Loot Crates: You should get more cash for skins you already own, otherwise you spend 500 - 2000 on a skin, only to get it again in a loot crate and gain 10 or 20 credits. I would just prefer cash over crates to be honest.
Edit: Thinking about it... Why not just have play mode with the option of Power-ups and ranked mode without any?
What about a Time Trial mode? Or at least a way to log and share your fastest times round tracks?