I've to agree with Konti that a one-man-tank is more fearsome.
And AfterDune has right too... one player in a tank has a big blind angle.
But Infantry and one tanker may work together

The 50cal may stay as a second seat... so the tanker has a gunner watching his back.
I think the tank is an other topic in comparison to a helo which has to be handled by two players.
i cant fly and aim with a helo gun
BUT i can drive and shoot with a tank! Keyboard and mouse work perfectly for that.
The tank commander in RL has so much power, that the crew is acting like one person. The main gunner in RL has a aiming system and cannon that wont be effected by the movement of the driver.
Right now in 0.6 the crew never will be able to act like a RLcrew and wont act like a one person crew. so this 3-player-tank-fix weakend the tank cause the devs splitted a RL one person crew with a better main gun system into 3 players who may work with VoIP but often wont. Right now mostly one player is driving the tank....he drives it into a camper position and starts shooting from the gunner postion. Thats not realistic too.
Always have a well visited public server in your mind, while im explaining this
But right now we are discussing a main topic called "RL vs gameplay" and i know many of you like a total strategic tactics mod BUT a game never will be realistic and i think some vehicles and rules are created to hardcore.
Everyone who wants to play on public servers with this big differnces between veterans and rookies will be frustrated soon.
And im frustrated that there are some "RLfixes" that dont really fit into this kind of mod.
I know that the engine is not really easy to handle but i hope that some features that got a more realistic feeling into this mod are still like a fix and not like a solution.
So I hope that old features like the one-man-tank may be discussed.
The topic about the rally point vs airdrop is worth discussing too.