I think non of the Halo games nailed vehicles completely so far. I will say something on front though: I had wonderful memories and a ton of fun with vehicles until Reach. From H4 onward the situation just got worse. The main issue imho is the addition of advanced movement mechanics becoming core elements of the gameplay instead of limited power ups. Anyway, this are the main issues from every main enry from my point of view (feel free to disagree):
Halo Combat Evolved / Custom Edition
Ghosts were too slow while Banshee’s fire power mattered only because of the green plasma bolt of doom (playable only PC also). Plus the life meter was way too high while never giving enough protection to the actual player. Human vehicles on the other side were undestructible while giving you zero protection towards sniper fire. Not to mention splatter was a question of touching something at a min. of 3km/h (or 1,86 Mph for my american friends out there)! X’D
Halo 2
Much better. All vehicles now are destructible, you can steal them now, Banshee’s are now usable on console (no bolt shot though, plasma fire does damage though and shots land were they are supposed to land), speed to splatter-damage makes sense now as well, but every heavier vehicle starting from the Warthog had way too many life.points. Not to mention that it was bound to the driver’s health meter now as well. If a team got two Scorpions or even Wraths good luck leaving the spawn point. The only good thing is, vehicles have weak points now. Focus on them and you can overcome them. It’s still hard and unbalanced like hell though.
Halo 3
Got a bit better thanks to EMP equipment, stationary weapons with great damage output against vehicles, anti-air missiles, plasma pistol secondary fire and better spawn points overall. That said all life system problems mentioned before still remain, and now it might be even worse. What made H3 vehicle combat so memorable though compared to H2 was thanks to the extremely diverse sandbox combined with amazing maps build around them. Sandtrap anyone? -Yoinking- Elephants?! Hell yes!
Halo Reach
Vehicles now have separate life bars to the driver, the sandbox got even more choices and the focus here is clearly on cooperative driving with maps heavily focused on Falcons, Warthogs and even the newcomer Revnant, while at the same time increasing the damage output of secondary turrets on Scorpions and Wraths. On the other side simple transportation now is useless due to loadouts (sprint and jetpacks first and foremost), not to mention people now can spawn with plasma pistols - aka the trolls heaven! Reach for me was the death of the Mongoose frankly. Another major problem was that vehicles got way too easily damaged by simple bullet fire… Three Spartans with DMRs can easily take down a Banshee for instance, common! And while Reach certainly offered maps build around vehicles, especially in Invasion, it just lacked the creativity and epicness H3 gave us three years prior.
Halo 4
Also known as “Plasma pistol troll eden of green destruction with personal vehicular torture chamber attached to it”. It’s a long but damn fitting title! Plus even when green bolts of death weren’t around (highly improbable), without vehicle specialized commendation driving around was pretty much an useless effort. Not to mention sprint is now a core mechanic. Halo 4 proves why sprint in Halo should never be a core mechanic! We got a Robot though. There is that! Doesn’t really fit Halo, it’s fun to use though! … so it’s okay, right? … I want to forget this game ever existed frankly! 
Halo 5 Guardian
343i added something small but great: press “A” to jump from seat to seat. You never know you need something until you get it! This aside Halo even with all the balancing problems it provided in vehicle combat until Reach it always was a fun experience at the end of the day. You spawned, turned around and fought for that alien flying machine of death. Now you only use them in Warzone and there is no fight for them, you select them - and of course lose them to EMP shots shortly after. It should be better in firefight, but the only thing it does is creating chaos, and not the fun one. Plus the cooperativeness is gone! All vehicles that are worthwhile only got one seat or provide little fire-power for the second driver.
Halo Infinite
Based on this the next Halo installment should have the following to make vehicles good again, or even better to prior tiles:
- No advanced movement as core mechanic - Higher life-span than Reach (maybe make it visible on the screen) - Separate life bars - Little damage received by gun-fire - Cooperative mindset (multiple seats, secondary turrets, support roles) - Weak-points - Map design build around terrain and flying vehicles - Interactive level design elements to counter or help vehicles (closed down secondary paths, light bridges, Elephants, EMP towers…)I also would love to see space combat making its introduction to MP. Let’s cross fingers for Hi!